stationary in distributions of numerical solutions for stochastic partial differential ... ·...
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Hindawi Publishing CorporationAbstract and Applied AnalysisVolume 2013 Article ID 752953 12 pageshttpdxdoiorg1011552013752953
Research ArticleStationary in Distributions of Numerical Solutions for StochasticPartial Differential Equations with Markovian Switching
Yi Shen1 and Yan Li12
1 Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China2 College of Science Huazhong Agriculture University Wuhan 430079 China
Correspondence should be addressed to Yi Shen yeeshen0912gmailcom
Received 30 December 2012 Accepted 24 February 2013
Academic Editor Qi Luo
Copyright copy 2013 Y Shen and Y Li This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
We investigate a class of stochastic partial differential equations with Markovian switching By using the Euler-Maruyama schemeboth in time and in space of mild solutions we derive sufficient conditions for the existence and uniqueness of the stationarydistributions of numerical solutions Finally one example is given to illustrate the theory
1 Introduction
The theory of numerical solutions of stochastic partialdifferential equations (SPDEs) has been well developed bymany authors [1ndash5] In [2] Debussche considered the errorof the Euler scheme for the nonlinear stochastic partialdifferential equations by using Malliavin calculus Gyongyand Millet [3] discussed the convergence rate of space timeapproximations for stochastic evolution equations Shardlow[5] investigated the numerical methods of the mild solutionsfor stochastic parabolic PDEs derived by space-time whitenoise by applying finite difference approach
On the other hand the parameters of SPDEs mayexperience abrupt changes caused by phenomena such ascomponent failures or repairs changing subsystem intercon-nections and abrupt environmental disturbances [6ndash9] andthe continuous-timeMarkov chains have been used to modelthese parameter jumps An important equation is a class ofSPDEs with Markovian switching
119889119883 (119905) = [119860119883 (119905) + 119891 (119883 (119905) 119903 (119905))] 119889119905
+ 119892 (119883 (119905) 119903 (119905)) 119889119882 (119905) 119905 ge 0
(1)
Here the state vector has two components 119883(119905) and 119903(119905) thefirst one is normally referred to as the state while the secondone is regarded as the mode In its operation the system willswitch from one mode to another one in a random way and
the switching among the modes is governed by the Markovchain 119903(119905)
Since only a few SPDEs with Markovian switchinghave explicit formulae numerical (approximate) schemes ofSPDEs with Markovian switching are becoming more andmore popular In this paper we will study the stationarydistribution of numerical solutions of SPDEs withMarkovianswitching Bao et al [10] investigated the stability in distribu-tion of mild solutions to SPDEs Bao and Yuan [11] discussedthe numerical approximation of stationary distribution forSPDEs For the stationary distribution of numerical solu-tions of stochastic differential equations in finite-dimensionalspace Mao et al [12] utilized the Euler-Maruyama schemewith variable step size to obtain the stationary distributionand they also proved that the probability measures inducedby the numerical solutions converge weakly to the stationarydistribution of the true solution But since the mild solutionsof SPDEs with Markovian switching do not have stochasticdifferential a significant consequence of this fact is that theIto formula cannot be used for mild solutions of SPDEs withMarkovian switching directly Consequently we generalizethe stationary distribution of numerical solutions of the finitedimensional stochastic differential equationswithMarkovianswitching to that of infinite dimensional cases
Motived by [11ndash13] we will show in this paper that themild solutions of SPDE with Markovian switching (1) have aunique stationary distribution for sufficiently small step size
2 Abstract and Applied Analysis
So this paper is organised as follows in Section 2 we givenecessary notations and define Euler-Maruyama scheme ofmild solutions In Section 3 we give some lemmas and themain result in this paper Finally we will give an example toillustrate the theory in Section 4
2 Statements of Problem
Throughout this paper unless otherwise specified we let(ΩF F
119905119905ge0P) be complete probability space with a
filtration F119905119905ge0
satisfying the usual conditions (ie it isincreasing and right continuous while F
0contains all P-
null sets) Let (119867 ⟨sdot sdot⟩119867 sdot
119867) be a real separable Hilbert
space and 119882(119905) an 119867-valued cylindrical Brownian motion(Wiener process) defined on the probability space Let 119868
119866be
the indicator function of a set 119866 Denote by (L(119867) sdot )and (LHS(119867) sdot HS) the family of bounded linear operatorsand Hilbert-Schmidt operator from 119867 into 119867 respectivelyLet 119903(119905) 119905 ge 0 be a right-continuous Markov chain on theprobability space taking values in a finite state space S =
1 2 119873 with the generator Γ = (120574119894119895)119873times119873
given by
P 119903 (119905 + 120575) = 119895 | 119903 (119905) = 119894 = 120574119894119895120575 + 119900 (120575) if 119894 = 1198951 + 120574119894119895120575 + 119900 (120575) if 119894 = 119895
(2)
where 120575 gt 0 Here 120574119894119895gt 0 is the transition rate from 119894 to 119895 if
119894 = 119895 while
120574119894119894= minussum
119895 = 119894
120574119894119895 (3)
We assume that the Markov chain 119903(sdot) is independent of theBrownian motion 119882(sdot) It is well known that almost everysample path of 119903(sdot) is a right-continuous step function withfinite number of simple jumps in any finite subinterval ofR+= [0 +infin)Consider SPDEs with Markovian switching on119867
119889119883 (119905) = [119860119883 (119905) + 119891 (119883 (119905) 119903 (119905))] 119889119905
+ 119892 (119883 (119905) 119903 (119905)) 119889119882 (119905) 119905 ge 0
(4)
with initial value 119883(0) = 119909 isin 119867 and 119903(0) = 119894 isin S Here119891 119867 times S rarr 119867 119892 119867 times S rarr LHS(119867) Throughout thepaper we impose the following assumptions
(A1) (119860D(119860)) is a self-adjoint operator on 119867 generatinga 1198620-semigroup 119890119860119905
119905ge0 such that 119890119860119905 le 119890minus120572119905 for
some120572 gt 0 In this caseminus119860 has discrete spectrum 0 lt1205881le 1205882le sdot sdot sdot le lim
119894rarrinfin120588119894= infin with corresponding
eigenbasis 119890119894119894ge1
of119867(A2) Both 119891 and 119892 are globally Lipschitz continuous That
is there exists a constant 119871 gt 0 such that
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
119867or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le 1198711003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 forall119909 119910 isin 119867 119895 isin S
(5)
(A3) There exist 120583 gt 0 and 120582119895gt 0 (119895 = 1 2 119873) such
that
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS
+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 forall119909 119910 isin 119867 119895 isin S
(6)
It is well known (see [1 8]) that under (A1)ndash(A3) (4) hasa unique mild solution 119883(119905) on 119905 ge 0 That is for any 119883(0) =119909 isin 119867 and 119903(0) = 119894 isin S there exists a unique 119867-valuedadapted process119883(119905) such that
119883(119905) = 119890119905119860119909 + int
119905
0
119890(119905minus119904)119860119891 (119883 (119904) 119903 (119904)) 119889119904
+ int
119905
0
119890(119905minus119904)119860119892 (119883 (119904) 119903 (119904)) 119889119882 (119904)
(7)
Moreover the pair119885(119905) = (119883(119905) 119903(119905)) is a time-homogeneousMarkov process
Remark 1 We observe that (A2) implies the following lineargrowth conditions
1003816100381610038161003816119891 (119909 119895)10038161003816100381610038162
119867or1003817100381710038171003817119892 (119909 119895)
10038171003817100381710038172
HS le 119871 (1 + 1199092
119867) forall119909 isin 119867 119895 isin S
(8)
where 119871 = 2max119895isinS(119871 or |119891(0 119895)|
2
119867or 119892(0 119895)
2
HS)
Remark 2 We also establish another property from (A3)
2120582119895⟨119909 119891 (119909 119895)⟩
119867+ 120582119895
1003817100381710038171003817119892 (119909 119895)10038171003817100381710038172
HS +119873
sum
119897=1
1205741198951198971205821198971199092
119867
le 2120582119895⟨119909 119891 (119909 119895) minus 119891 (0 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (0 119895)10038171003817100381710038172
HS +119873
sum
119897=1
1205741198951198971205821198971199092
119867
+ 2120582119895⟨119909 119891 (0 119895)⟩
119867
+ 2120582119895⟨119892 (119909 119895) minus 119892 (0 119895) 119892 (0 119895)⟩HS + 120582119895
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS
le minus1205831199092
119867+120583
41199092
119867+41205822
119895
1003817100381710038171003817119891 (0 119895)1003817100381710038171003817119867
120583
+120583
4119871
1003817100381710038171003817119892 (119909 119895) minus 119892 (0 119895)10038171003817100381710038172
HS
+41198711205822
119895
120583
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS + 1205821198951003817100381710038171003817119892 (0 119895)
10038171003817100381710038172
HS
le minus1205831199092
119867+120583
41199092
119867+120583
41199092
119867+41205822
119895
1003817100381710038171003817119891 (0 119895)1003817100381710038171003817119867
120583
Abstract and Applied Analysis 3
+41198711205822
119895
120583
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS + 1205821198951003817100381710038171003817119892 (0 119895)
10038171003817100381710038172
HS
le minus120583
21199092
119867+ 1205721 forall119909 isin 119867 119895 isin S
(9)
where1205721= max
119895isinS[(41205822
119895 119891(0 119895)
2
119867120583) +(4119871120582
2
119895120583) 119892(0 119895)
2
HS + 120582119895 119892(0 119895)2
HS] and ⟨119879 119878⟩HS = suminfin
119894=1⟨119879119890119894 119878119890119895⟩119867for
119878 119879 isinLHS(119867)
Denote by119885119909119894(119905) = (119883119909119894(119905) 119903119894(119905)) themild solution of (4)starting from (119909 119894) isin 119867 times S For any subset 119860 isin B(119867) 119861 subS let P
119905((119909 119894) 119860 times 119861) be the probability measure induced by
119885119909119894(119905) 119905 ge 0 Namely
P119905((119909 119894) 119860 times 119861) = P (119885
119909119894isin 119860 times 119861) (10)
whereB(119867) is the family of the Borel subset of119867Denote byP(119867timesS) the family by all probabilitymeasures
on 119867 times S For 1198751 1198752isin P(119867 times S) define the metric 119889L as
follows
119889L (1198751 1198752)
= sup120593isinL
10038161003816100381610038161003816100381610038161003816100381610038161003816
119873
sum
119895=1
int119867
120593 (119906 119895) 1198751(119889119906 119895) minus
119873
sum
119895=1
int120593 (119906 119895) 1198752(119889119906 119895)
10038161003816100381610038161003816100381610038161003816100381610038161003816
(11)
where L = 120593 119867 times S rarr R |120593(119906 119895) minus 120593(V 119897)| le 119906 minus V119867+
|119895 minus 119897| and |120593(119906 119895)| le 1 for 119906 V isin 119870 119895 119897 isin S
Remark 3 It is known that the weak convergence of probabil-ity measures is a metric concept with respect to classes of testfunction In other words a sequence of probability measures119875119896119896ge1
of P(119867 times S) converges weakly to a probabilitymeasure 119875
0isin P(119867timesS) if and only if lim
119896rarrinfin119889L(119875119896 1198750) = 0
Definition 4 The mild solution 119885(119905) = (119883(119905) 119903(119905)) of (4) issaid to have a stationary distribution 120587(sdot times sdot) isin P(119867 times S) ifthe probability measure P
119905((119909 119894) (sdot times sdot)) converges weakly to
120587(sdottimessdot) as 119905 rarr infin for every 119894 isin S and every 119909 isin 119880 a boundedsubset of119867 that is
lim119905rarrinfin
119889L (P119905 (119909 119894) 120587 (sdot times sdot))
= lim119905rarrinfin
(sup120593isinL
10038161003816100381610038161003816100381610038161003816100381610038161003816
E120593 (119885119909119894(119905))
minus
119873
sum
119895=1
int119867
120593 (119906 119895) 120587 (119889119906 119895)
10038161003816100381610038161003816100381610038161003816100381610038161003816
) = 0
(12)
By Theorem 31 in [10] and Theorem 31 in [14] we havethe following
Theorem 5 Under (A1)ndash(A3) the Markov process 119885(119905) has aunique stationary distribution 120587(sdot times sdot) isin P(119867 times S)
For any 119899 ge 1 let 120587119899 119867 rarr 119867
119899= Span119890
1 1198902 119890
119899
be the orthogonal projection Consider SPDEs with Marko-vian switching on119867
119899
119889119883119899(119905) = [119860
119899119883119899(119905) + 119891
119899(119883119899(119905) 119903 (119905))] 119889119905
+ 119892119899(119883119899(119905) 119903 (119905)) 119889119882 (119905)
(13)
with initial data 119883119899(0) = 120587119899119909 = sum
119899
119894=1⟨119909 119890119894⟩119867119890119894 119909 isin 119867 Here
119860119899= 120587119899119860 119891119899= 120587119899119891 119892119899= 120587119899119892
Therefore we can observe that
119860119899119909 = 119860119909 119890
119905119860119899119909= 119890119905119860119909 ⟨119909 119891
119899⟩119867= ⟨119909 119891⟩
119867
⟨119909 119892119899⟩119867= ⟨119909 119892⟩
119867 forall119909 isin 119867
119899
(14)
By the property of the projection operator and (A2) we have
1003817100381710038171003817119860119899 (119909 minus 119910)10038171003817100381710038172
119867or1003817100381710038171003817119891119899 (119909 119895) minus 119891119899 (119910 119895)
10038171003817100381710038172
119867
or1003817100381710038171003817119892119899 (119909 119895) minus 119892119899 (119910 119895)
10038171003817100381710038172
HS
le 1205822
119899
1003817100381710038171003817(119909 minus 119910)10038171003817100381710038172
119867or1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)
10038171003817100381710038172
119867
or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS le (1205822
119899or 119871)1003817100381710038171003817(119909 minus 119910)
10038171003817100381710038172
119867
forall119909 119910 isin 119867119899 119895 isin S
(15)
Hence (13) admits a unique strong solution 119883119899(119905)119905ge0
on119867119899
(see [8])We now introduce an Euler-Maruyama based computa-
tionalmethodThemethodmakes use of the following lemma(see [15])
Lemma 6 Given Δ gt 0 then 119903(119896Δ) 119896 = 0 1 2 is adiscrete Markov chain with the one-step transition probabilitymatrix
119875 (Δ) = (119875119894119895(Δ))119873times119873= 119890ΔΓ (16)
Given a fixed step size Δ gt 0 and the one-step transitionprobability matrix 119875(Δ) in (16) the discrete Markov chain119903(119896Δ) 119896 = 0 1 2 can be simulated as follows let119903(0) = 119894
0 and compute a pseudorandom number 120585
1from the
uniform (0 1) distributionDefine
119903 (Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(0)119895(Δ)
le 1205851
lt
119894
sum119895=1
119875119903(0)119895(Δ)
119873
119873minus1
sum119895=1
119875119903(0)119895(Δ) le 120585
1
(17)
4 Abstract and Applied Analysis
where we set sum0119895=1119875119903(0)119895(Δ) = 0 as usual Having computed
119903(0) 119903(Δ) 119903(119896Δ) we can compute 119903((119896 + 1)Δ) by drawinga uniform (0 1) pseudorandom number 120585
119896+1and setting
119903 ((119896 + 1) Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(119896Δ)119895
(Δ)
le 120585119896+1lt
119894
sum119895=1
119875119903(119896Δ)119895
(Δ)
119873
119873minus1
sum119895=1
119875119903(119896Δ)119895
(Δ) le 120585119896+1
(18)
The procedure can be carried out repeatedly to obtain moretrajectories
We now define the Euler-Maruyama approximation for(13) For a stepsize Δ isin (0 1) the discrete approximation119884119899
(119896Δ) asymp 119883119899(119896Δ) is formed by simulating from 119884119899(0) =
120587119899119909 119903(0) = 119903
0 and
119884119899
((119896 + 1) Δ)
= 119890Δ119860119899 119884119899
(119896Δ) + 119891119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ
+119892119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ119882119896
(19)
where Δ119882119896= 119882((119896 + 1)Δ) minus 119882(119896Δ))
To carry out our analysis conveniently we give thecontinuous Euler-Maruyama approximation solution whichis defined by
119884119899(119905) = 119890
119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= 119890119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(20)
where lfloor119905rfloor = [119905Δ]Δ and [119905Δ] denotes the integer part of 119905Δand 119884119899(0) = 119884119899(0) = 120587
119899119909 and 119884119899(119896Δ) = 119884119899(119896Δ)
It is obvious that119884119899(119905) coincides with the discrete approx-imation solution at the gridpoints For any Borel set 119860 isinB(119867119899) 119909 isin 119867
119899 119894 119895 isin S let 119885
119899
(119896Δ) = (119884119899
(119896Δ) 119903(119896Δ))
P119899Δ((119909 119894) 119860 times 119895)
= P (119885119899
(Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
P119899Δ
119896((119909 119894) 119860 times 119895)
= P (119885119899
(119896Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
(21)
Following the argument of Theorem 5 in [13] we have thefollowing
Lemma 7 119885 119899(119896Δ)119896ge0
is a homogeneous Markov processwith the transition probability kernel P119899Δ((119909 119894) 119860 times 119895)
To highlight the initial value we will use notation119885119899(119909119894)
(119896Δ)
Definition 8 For a given stepsize Δ gt 0 119885119899(119909119894)
(119896Δ)119896ge0
issaid to have a stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times
S) if the 119896-step transition probability kernel P119899Δ119896((119909 119894) sdot times sdot)
converges weakly to 120587119899Δ(sdot times sdot) as 119896 rarr infin for every (119909 119894) isin119867119899times S that is
lim119896rarrinfin
119889L (119875119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (22)
We will establish our result of this paper in Section 3
Theorem 9 Under (A1)ndash(A3) for a given stepsize Δ gt 0and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has a uniquestationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
3 Stationary in Distribution ofNumerical Solutions
In this section we shall present some useful lemmas andproveTheorem 9 In what follows119862 gt 0 is a generic constantwhose values may change from line to line
For any initial value (119909 119894) let 119884119899119909119894(119905) be the continuousEuler-Maruyama solution of (20) and starting from (119909 119894) isin119867 times S Let 119883119909119894(119905) be the mild solution of (4) and startingfrom (119909 119894) isin 119867 times S
Lemma 10 Under (A1)ndash(A3) then
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119909119894(lfloor119905rfloor)10038171003817100381710038171003817
2
119867
le 3 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(23)
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119884119899119909119894(lfloor119905rfloor) = 119884119899(lfloor119905rfloor) From(20) we have
119884119899(lfloor119905rfloor) = 119890
lfloor119905rfloor119860120587119899119909 + int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(24)
Abstract and Applied Analysis 5
Thus
119884119899(119905) minus 119884
119899(lfloor119905rfloor)
= 119890(119905minuslfloor119905rfloor)119860
times (119890lfloor119905rfloor119860120587119899119909
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904) )
minus 119884119899(lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= (119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(25)
Then by theHolder inequality and the Ito isometrywe obtain
E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 3E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
(26)
From (A1) we have
E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
= E
1003817100381710038171003817100381710038171003817100381710038171003817
119899
sum
119894=1
(119890minus120588119894(119905minuslfloor119905rfloor)
minus 1) ⟨119884119899(lfloor119905rfloor) 119890
119894⟩119867119890119894
1003817100381710038171003817100381710038171003817100381710038171003817
2
119867
le (1 minus 119890minus120588119899(119905minuslfloor119905rfloor)
)2
E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 1205882
119899Δ2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
(27)
here we use the fundamental inequality 1 minus 119890minus119886 le 119886 119886 gt 0And by (8) it follows that
Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
le 2119871Δ (1 + E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(28)
Substituting (27) and (28) into (26) the desired assertion (23)follows
Lemma 11 Under (A1)ndash(A3) if Δ lt min1 13(1205882119899+ 2119871)
((4120572119901 + 120583)(8119902 + 41199021205882
119899119871+4119902119871 + 24119902 + 6119902119871(120588
2
119899+2119871)))
2
thenthere is a constant119862 gt 0 that depends on the initial value 119909 butis independent ofΔ such that the continuous Euler-Maruyamasolution of (20) has
sup119905ge0
E10038171003817100381710038171003817119884119899119909119894(119905)10038171003817100381710038171003817119867le 119862 (29)
where 119902 = max1le119894le119873
120582119894 119901 = min
1le119894le119873120582119894
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119903119894(119896Δ) = 119903(119896Δ) From (20) wehave the following differential form
119889119884119899(119905)
= 119860119884119899(119905) + 119890
(119905minuslfloor119905rfloor)119860119891119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119905
+ 119890(119905minuslfloor119905rfloor)119860
119892119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119882 (119905)
(30)
with 119884119899(0) = 120587119899119909
Let119881(119909 119894) = 120582119894 1199092
119867 By the generalised Ito formula for
any 120579 gt 0 we derive from (30) that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1205821198941199092
119867+ Eint
119905
0
119890120579119904120582119903(119904)
times 1205791003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ 2⟨119884
119899(119904) 119860119884
119899(119904)⟩119867
+ 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892119899 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
6 Abstract and Applied Analysis
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
(31)
By the fundamental transformation we obtain that
⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))⟩
119867
= ⟨119884119899(119905) 119891 (119884
119899(119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1) 119891 (119884119899 (119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119891 (119884119899(119905) 119903 (119905))) ⟩
119867
(32)
By Hold inequality we have
1003817100381710038171003817119892 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
=1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
minus (119892 (119884119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(33)
Then from (31) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2⟨119884119899(119904) 119891 (119884
119899(119904) 119903 (119904))⟩
119867
+1003817100381710038171003817119892 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus120583
2Eint119905
0
119890120579119904119884 (119904)
2
119867119889119904 + 120572
1int
119905
0
119890120579119904119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
(119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
= 1198691(119905) + 119869
2(119905) + 119869
3(119905) + 119869
4(119905)
(34)
By the elemental inequality 2119886119887 le (1198862120581)+1205811198872 119886 119887 isin R 120581 gt0 and (8) (27) we obtain that for Δ lt 1
1198692(119905) le Eint
119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times 119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Volume 2014
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Stochastic AnalysisInternational Journal of
2 Abstract and Applied Analysis
So this paper is organised as follows in Section 2 we givenecessary notations and define Euler-Maruyama scheme ofmild solutions In Section 3 we give some lemmas and themain result in this paper Finally we will give an example toillustrate the theory in Section 4
2 Statements of Problem
Throughout this paper unless otherwise specified we let(ΩF F
119905119905ge0P) be complete probability space with a
filtration F119905119905ge0
satisfying the usual conditions (ie it isincreasing and right continuous while F
0contains all P-
null sets) Let (119867 ⟨sdot sdot⟩119867 sdot
119867) be a real separable Hilbert
space and 119882(119905) an 119867-valued cylindrical Brownian motion(Wiener process) defined on the probability space Let 119868
119866be
the indicator function of a set 119866 Denote by (L(119867) sdot )and (LHS(119867) sdot HS) the family of bounded linear operatorsand Hilbert-Schmidt operator from 119867 into 119867 respectivelyLet 119903(119905) 119905 ge 0 be a right-continuous Markov chain on theprobability space taking values in a finite state space S =
1 2 119873 with the generator Γ = (120574119894119895)119873times119873
given by
P 119903 (119905 + 120575) = 119895 | 119903 (119905) = 119894 = 120574119894119895120575 + 119900 (120575) if 119894 = 1198951 + 120574119894119895120575 + 119900 (120575) if 119894 = 119895
(2)
where 120575 gt 0 Here 120574119894119895gt 0 is the transition rate from 119894 to 119895 if
119894 = 119895 while
120574119894119894= minussum
119895 = 119894
120574119894119895 (3)
We assume that the Markov chain 119903(sdot) is independent of theBrownian motion 119882(sdot) It is well known that almost everysample path of 119903(sdot) is a right-continuous step function withfinite number of simple jumps in any finite subinterval ofR+= [0 +infin)Consider SPDEs with Markovian switching on119867
119889119883 (119905) = [119860119883 (119905) + 119891 (119883 (119905) 119903 (119905))] 119889119905
+ 119892 (119883 (119905) 119903 (119905)) 119889119882 (119905) 119905 ge 0
(4)
with initial value 119883(0) = 119909 isin 119867 and 119903(0) = 119894 isin S Here119891 119867 times S rarr 119867 119892 119867 times S rarr LHS(119867) Throughout thepaper we impose the following assumptions
(A1) (119860D(119860)) is a self-adjoint operator on 119867 generatinga 1198620-semigroup 119890119860119905
119905ge0 such that 119890119860119905 le 119890minus120572119905 for
some120572 gt 0 In this caseminus119860 has discrete spectrum 0 lt1205881le 1205882le sdot sdot sdot le lim
119894rarrinfin120588119894= infin with corresponding
eigenbasis 119890119894119894ge1
of119867(A2) Both 119891 and 119892 are globally Lipschitz continuous That
is there exists a constant 119871 gt 0 such that
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
119867or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le 1198711003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 forall119909 119910 isin 119867 119895 isin S
(5)
(A3) There exist 120583 gt 0 and 120582119895gt 0 (119895 = 1 2 119873) such
that
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS
+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 forall119909 119910 isin 119867 119895 isin S
(6)
It is well known (see [1 8]) that under (A1)ndash(A3) (4) hasa unique mild solution 119883(119905) on 119905 ge 0 That is for any 119883(0) =119909 isin 119867 and 119903(0) = 119894 isin S there exists a unique 119867-valuedadapted process119883(119905) such that
119883(119905) = 119890119905119860119909 + int
119905
0
119890(119905minus119904)119860119891 (119883 (119904) 119903 (119904)) 119889119904
+ int
119905
0
119890(119905minus119904)119860119892 (119883 (119904) 119903 (119904)) 119889119882 (119904)
(7)
Moreover the pair119885(119905) = (119883(119905) 119903(119905)) is a time-homogeneousMarkov process
Remark 1 We observe that (A2) implies the following lineargrowth conditions
1003816100381610038161003816119891 (119909 119895)10038161003816100381610038162
119867or1003817100381710038171003817119892 (119909 119895)
10038171003817100381710038172
HS le 119871 (1 + 1199092
119867) forall119909 isin 119867 119895 isin S
(8)
where 119871 = 2max119895isinS(119871 or |119891(0 119895)|
2
119867or 119892(0 119895)
2
HS)
Remark 2 We also establish another property from (A3)
2120582119895⟨119909 119891 (119909 119895)⟩
119867+ 120582119895
1003817100381710038171003817119892 (119909 119895)10038171003817100381710038172
HS +119873
sum
119897=1
1205741198951198971205821198971199092
119867
le 2120582119895⟨119909 119891 (119909 119895) minus 119891 (0 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (0 119895)10038171003817100381710038172
HS +119873
sum
119897=1
1205741198951198971205821198971199092
119867
+ 2120582119895⟨119909 119891 (0 119895)⟩
119867
+ 2120582119895⟨119892 (119909 119895) minus 119892 (0 119895) 119892 (0 119895)⟩HS + 120582119895
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS
le minus1205831199092
119867+120583
41199092
119867+41205822
119895
1003817100381710038171003817119891 (0 119895)1003817100381710038171003817119867
120583
+120583
4119871
1003817100381710038171003817119892 (119909 119895) minus 119892 (0 119895)10038171003817100381710038172
HS
+41198711205822
119895
120583
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS + 1205821198951003817100381710038171003817119892 (0 119895)
10038171003817100381710038172
HS
le minus1205831199092
119867+120583
41199092
119867+120583
41199092
119867+41205822
119895
1003817100381710038171003817119891 (0 119895)1003817100381710038171003817119867
120583
Abstract and Applied Analysis 3
+41198711205822
119895
120583
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS + 1205821198951003817100381710038171003817119892 (0 119895)
10038171003817100381710038172
HS
le minus120583
21199092
119867+ 1205721 forall119909 isin 119867 119895 isin S
(9)
where1205721= max
119895isinS[(41205822
119895 119891(0 119895)
2
119867120583) +(4119871120582
2
119895120583) 119892(0 119895)
2
HS + 120582119895 119892(0 119895)2
HS] and ⟨119879 119878⟩HS = suminfin
119894=1⟨119879119890119894 119878119890119895⟩119867for
119878 119879 isinLHS(119867)
Denote by119885119909119894(119905) = (119883119909119894(119905) 119903119894(119905)) themild solution of (4)starting from (119909 119894) isin 119867 times S For any subset 119860 isin B(119867) 119861 subS let P
119905((119909 119894) 119860 times 119861) be the probability measure induced by
119885119909119894(119905) 119905 ge 0 Namely
P119905((119909 119894) 119860 times 119861) = P (119885
119909119894isin 119860 times 119861) (10)
whereB(119867) is the family of the Borel subset of119867Denote byP(119867timesS) the family by all probabilitymeasures
on 119867 times S For 1198751 1198752isin P(119867 times S) define the metric 119889L as
follows
119889L (1198751 1198752)
= sup120593isinL
10038161003816100381610038161003816100381610038161003816100381610038161003816
119873
sum
119895=1
int119867
120593 (119906 119895) 1198751(119889119906 119895) minus
119873
sum
119895=1
int120593 (119906 119895) 1198752(119889119906 119895)
10038161003816100381610038161003816100381610038161003816100381610038161003816
(11)
where L = 120593 119867 times S rarr R |120593(119906 119895) minus 120593(V 119897)| le 119906 minus V119867+
|119895 minus 119897| and |120593(119906 119895)| le 1 for 119906 V isin 119870 119895 119897 isin S
Remark 3 It is known that the weak convergence of probabil-ity measures is a metric concept with respect to classes of testfunction In other words a sequence of probability measures119875119896119896ge1
of P(119867 times S) converges weakly to a probabilitymeasure 119875
0isin P(119867timesS) if and only if lim
119896rarrinfin119889L(119875119896 1198750) = 0
Definition 4 The mild solution 119885(119905) = (119883(119905) 119903(119905)) of (4) issaid to have a stationary distribution 120587(sdot times sdot) isin P(119867 times S) ifthe probability measure P
119905((119909 119894) (sdot times sdot)) converges weakly to
120587(sdottimessdot) as 119905 rarr infin for every 119894 isin S and every 119909 isin 119880 a boundedsubset of119867 that is
lim119905rarrinfin
119889L (P119905 (119909 119894) 120587 (sdot times sdot))
= lim119905rarrinfin
(sup120593isinL
10038161003816100381610038161003816100381610038161003816100381610038161003816
E120593 (119885119909119894(119905))
minus
119873
sum
119895=1
int119867
120593 (119906 119895) 120587 (119889119906 119895)
10038161003816100381610038161003816100381610038161003816100381610038161003816
) = 0
(12)
By Theorem 31 in [10] and Theorem 31 in [14] we havethe following
Theorem 5 Under (A1)ndash(A3) the Markov process 119885(119905) has aunique stationary distribution 120587(sdot times sdot) isin P(119867 times S)
For any 119899 ge 1 let 120587119899 119867 rarr 119867
119899= Span119890
1 1198902 119890
119899
be the orthogonal projection Consider SPDEs with Marko-vian switching on119867
119899
119889119883119899(119905) = [119860
119899119883119899(119905) + 119891
119899(119883119899(119905) 119903 (119905))] 119889119905
+ 119892119899(119883119899(119905) 119903 (119905)) 119889119882 (119905)
(13)
with initial data 119883119899(0) = 120587119899119909 = sum
119899
119894=1⟨119909 119890119894⟩119867119890119894 119909 isin 119867 Here
119860119899= 120587119899119860 119891119899= 120587119899119891 119892119899= 120587119899119892
Therefore we can observe that
119860119899119909 = 119860119909 119890
119905119860119899119909= 119890119905119860119909 ⟨119909 119891
119899⟩119867= ⟨119909 119891⟩
119867
⟨119909 119892119899⟩119867= ⟨119909 119892⟩
119867 forall119909 isin 119867
119899
(14)
By the property of the projection operator and (A2) we have
1003817100381710038171003817119860119899 (119909 minus 119910)10038171003817100381710038172
119867or1003817100381710038171003817119891119899 (119909 119895) minus 119891119899 (119910 119895)
10038171003817100381710038172
119867
or1003817100381710038171003817119892119899 (119909 119895) minus 119892119899 (119910 119895)
10038171003817100381710038172
HS
le 1205822
119899
1003817100381710038171003817(119909 minus 119910)10038171003817100381710038172
119867or1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)
10038171003817100381710038172
119867
or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS le (1205822
119899or 119871)1003817100381710038171003817(119909 minus 119910)
10038171003817100381710038172
119867
forall119909 119910 isin 119867119899 119895 isin S
(15)
Hence (13) admits a unique strong solution 119883119899(119905)119905ge0
on119867119899
(see [8])We now introduce an Euler-Maruyama based computa-
tionalmethodThemethodmakes use of the following lemma(see [15])
Lemma 6 Given Δ gt 0 then 119903(119896Δ) 119896 = 0 1 2 is adiscrete Markov chain with the one-step transition probabilitymatrix
119875 (Δ) = (119875119894119895(Δ))119873times119873= 119890ΔΓ (16)
Given a fixed step size Δ gt 0 and the one-step transitionprobability matrix 119875(Δ) in (16) the discrete Markov chain119903(119896Δ) 119896 = 0 1 2 can be simulated as follows let119903(0) = 119894
0 and compute a pseudorandom number 120585
1from the
uniform (0 1) distributionDefine
119903 (Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(0)119895(Δ)
le 1205851
lt
119894
sum119895=1
119875119903(0)119895(Δ)
119873
119873minus1
sum119895=1
119875119903(0)119895(Δ) le 120585
1
(17)
4 Abstract and Applied Analysis
where we set sum0119895=1119875119903(0)119895(Δ) = 0 as usual Having computed
119903(0) 119903(Δ) 119903(119896Δ) we can compute 119903((119896 + 1)Δ) by drawinga uniform (0 1) pseudorandom number 120585
119896+1and setting
119903 ((119896 + 1) Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(119896Δ)119895
(Δ)
le 120585119896+1lt
119894
sum119895=1
119875119903(119896Δ)119895
(Δ)
119873
119873minus1
sum119895=1
119875119903(119896Δ)119895
(Δ) le 120585119896+1
(18)
The procedure can be carried out repeatedly to obtain moretrajectories
We now define the Euler-Maruyama approximation for(13) For a stepsize Δ isin (0 1) the discrete approximation119884119899
(119896Δ) asymp 119883119899(119896Δ) is formed by simulating from 119884119899(0) =
120587119899119909 119903(0) = 119903
0 and
119884119899
((119896 + 1) Δ)
= 119890Δ119860119899 119884119899
(119896Δ) + 119891119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ
+119892119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ119882119896
(19)
where Δ119882119896= 119882((119896 + 1)Δ) minus 119882(119896Δ))
To carry out our analysis conveniently we give thecontinuous Euler-Maruyama approximation solution whichis defined by
119884119899(119905) = 119890
119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= 119890119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(20)
where lfloor119905rfloor = [119905Δ]Δ and [119905Δ] denotes the integer part of 119905Δand 119884119899(0) = 119884119899(0) = 120587
119899119909 and 119884119899(119896Δ) = 119884119899(119896Δ)
It is obvious that119884119899(119905) coincides with the discrete approx-imation solution at the gridpoints For any Borel set 119860 isinB(119867119899) 119909 isin 119867
119899 119894 119895 isin S let 119885
119899
(119896Δ) = (119884119899
(119896Δ) 119903(119896Δ))
P119899Δ((119909 119894) 119860 times 119895)
= P (119885119899
(Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
P119899Δ
119896((119909 119894) 119860 times 119895)
= P (119885119899
(119896Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
(21)
Following the argument of Theorem 5 in [13] we have thefollowing
Lemma 7 119885 119899(119896Δ)119896ge0
is a homogeneous Markov processwith the transition probability kernel P119899Δ((119909 119894) 119860 times 119895)
To highlight the initial value we will use notation119885119899(119909119894)
(119896Δ)
Definition 8 For a given stepsize Δ gt 0 119885119899(119909119894)
(119896Δ)119896ge0
issaid to have a stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times
S) if the 119896-step transition probability kernel P119899Δ119896((119909 119894) sdot times sdot)
converges weakly to 120587119899Δ(sdot times sdot) as 119896 rarr infin for every (119909 119894) isin119867119899times S that is
lim119896rarrinfin
119889L (119875119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (22)
We will establish our result of this paper in Section 3
Theorem 9 Under (A1)ndash(A3) for a given stepsize Δ gt 0and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has a uniquestationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
3 Stationary in Distribution ofNumerical Solutions
In this section we shall present some useful lemmas andproveTheorem 9 In what follows119862 gt 0 is a generic constantwhose values may change from line to line
For any initial value (119909 119894) let 119884119899119909119894(119905) be the continuousEuler-Maruyama solution of (20) and starting from (119909 119894) isin119867 times S Let 119883119909119894(119905) be the mild solution of (4) and startingfrom (119909 119894) isin 119867 times S
Lemma 10 Under (A1)ndash(A3) then
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119909119894(lfloor119905rfloor)10038171003817100381710038171003817
2
119867
le 3 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(23)
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119884119899119909119894(lfloor119905rfloor) = 119884119899(lfloor119905rfloor) From(20) we have
119884119899(lfloor119905rfloor) = 119890
lfloor119905rfloor119860120587119899119909 + int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(24)
Abstract and Applied Analysis 5
Thus
119884119899(119905) minus 119884
119899(lfloor119905rfloor)
= 119890(119905minuslfloor119905rfloor)119860
times (119890lfloor119905rfloor119860120587119899119909
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904) )
minus 119884119899(lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= (119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(25)
Then by theHolder inequality and the Ito isometrywe obtain
E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 3E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
(26)
From (A1) we have
E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
= E
1003817100381710038171003817100381710038171003817100381710038171003817
119899
sum
119894=1
(119890minus120588119894(119905minuslfloor119905rfloor)
minus 1) ⟨119884119899(lfloor119905rfloor) 119890
119894⟩119867119890119894
1003817100381710038171003817100381710038171003817100381710038171003817
2
119867
le (1 minus 119890minus120588119899(119905minuslfloor119905rfloor)
)2
E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 1205882
119899Δ2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
(27)
here we use the fundamental inequality 1 minus 119890minus119886 le 119886 119886 gt 0And by (8) it follows that
Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
le 2119871Δ (1 + E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(28)
Substituting (27) and (28) into (26) the desired assertion (23)follows
Lemma 11 Under (A1)ndash(A3) if Δ lt min1 13(1205882119899+ 2119871)
((4120572119901 + 120583)(8119902 + 41199021205882
119899119871+4119902119871 + 24119902 + 6119902119871(120588
2
119899+2119871)))
2
thenthere is a constant119862 gt 0 that depends on the initial value 119909 butis independent ofΔ such that the continuous Euler-Maruyamasolution of (20) has
sup119905ge0
E10038171003817100381710038171003817119884119899119909119894(119905)10038171003817100381710038171003817119867le 119862 (29)
where 119902 = max1le119894le119873
120582119894 119901 = min
1le119894le119873120582119894
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119903119894(119896Δ) = 119903(119896Δ) From (20) wehave the following differential form
119889119884119899(119905)
= 119860119884119899(119905) + 119890
(119905minuslfloor119905rfloor)119860119891119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119905
+ 119890(119905minuslfloor119905rfloor)119860
119892119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119882 (119905)
(30)
with 119884119899(0) = 120587119899119909
Let119881(119909 119894) = 120582119894 1199092
119867 By the generalised Ito formula for
any 120579 gt 0 we derive from (30) that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1205821198941199092
119867+ Eint
119905
0
119890120579119904120582119903(119904)
times 1205791003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ 2⟨119884
119899(119904) 119860119884
119899(119904)⟩119867
+ 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892119899 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
6 Abstract and Applied Analysis
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
(31)
By the fundamental transformation we obtain that
⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))⟩
119867
= ⟨119884119899(119905) 119891 (119884
119899(119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1) 119891 (119884119899 (119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119891 (119884119899(119905) 119903 (119905))) ⟩
119867
(32)
By Hold inequality we have
1003817100381710038171003817119892 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
=1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
minus (119892 (119884119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(33)
Then from (31) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2⟨119884119899(119904) 119891 (119884
119899(119904) 119903 (119904))⟩
119867
+1003817100381710038171003817119892 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus120583
2Eint119905
0
119890120579119904119884 (119904)
2
119867119889119904 + 120572
1int
119905
0
119890120579119904119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
(119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
= 1198691(119905) + 119869
2(119905) + 119869
3(119905) + 119869
4(119905)
(34)
By the elemental inequality 2119886119887 le (1198862120581)+1205811198872 119886 119887 isin R 120581 gt0 and (8) (27) we obtain that for Δ lt 1
1198692(119905) le Eint
119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times 119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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Volume 2014
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Stochastic AnalysisInternational Journal of
Abstract and Applied Analysis 3
+41198711205822
119895
120583
1003817100381710038171003817119892 (0 119895)10038171003817100381710038172
HS + 1205821198951003817100381710038171003817119892 (0 119895)
10038171003817100381710038172
HS
le minus120583
21199092
119867+ 1205721 forall119909 isin 119867 119895 isin S
(9)
where1205721= max
119895isinS[(41205822
119895 119891(0 119895)
2
119867120583) +(4119871120582
2
119895120583) 119892(0 119895)
2
HS + 120582119895 119892(0 119895)2
HS] and ⟨119879 119878⟩HS = suminfin
119894=1⟨119879119890119894 119878119890119895⟩119867for
119878 119879 isinLHS(119867)
Denote by119885119909119894(119905) = (119883119909119894(119905) 119903119894(119905)) themild solution of (4)starting from (119909 119894) isin 119867 times S For any subset 119860 isin B(119867) 119861 subS let P
119905((119909 119894) 119860 times 119861) be the probability measure induced by
119885119909119894(119905) 119905 ge 0 Namely
P119905((119909 119894) 119860 times 119861) = P (119885
119909119894isin 119860 times 119861) (10)
whereB(119867) is the family of the Borel subset of119867Denote byP(119867timesS) the family by all probabilitymeasures
on 119867 times S For 1198751 1198752isin P(119867 times S) define the metric 119889L as
follows
119889L (1198751 1198752)
= sup120593isinL
10038161003816100381610038161003816100381610038161003816100381610038161003816
119873
sum
119895=1
int119867
120593 (119906 119895) 1198751(119889119906 119895) minus
119873
sum
119895=1
int120593 (119906 119895) 1198752(119889119906 119895)
10038161003816100381610038161003816100381610038161003816100381610038161003816
(11)
where L = 120593 119867 times S rarr R |120593(119906 119895) minus 120593(V 119897)| le 119906 minus V119867+
|119895 minus 119897| and |120593(119906 119895)| le 1 for 119906 V isin 119870 119895 119897 isin S
Remark 3 It is known that the weak convergence of probabil-ity measures is a metric concept with respect to classes of testfunction In other words a sequence of probability measures119875119896119896ge1
of P(119867 times S) converges weakly to a probabilitymeasure 119875
0isin P(119867timesS) if and only if lim
119896rarrinfin119889L(119875119896 1198750) = 0
Definition 4 The mild solution 119885(119905) = (119883(119905) 119903(119905)) of (4) issaid to have a stationary distribution 120587(sdot times sdot) isin P(119867 times S) ifthe probability measure P
119905((119909 119894) (sdot times sdot)) converges weakly to
120587(sdottimessdot) as 119905 rarr infin for every 119894 isin S and every 119909 isin 119880 a boundedsubset of119867 that is
lim119905rarrinfin
119889L (P119905 (119909 119894) 120587 (sdot times sdot))
= lim119905rarrinfin
(sup120593isinL
10038161003816100381610038161003816100381610038161003816100381610038161003816
E120593 (119885119909119894(119905))
minus
119873
sum
119895=1
int119867
120593 (119906 119895) 120587 (119889119906 119895)
10038161003816100381610038161003816100381610038161003816100381610038161003816
) = 0
(12)
By Theorem 31 in [10] and Theorem 31 in [14] we havethe following
Theorem 5 Under (A1)ndash(A3) the Markov process 119885(119905) has aunique stationary distribution 120587(sdot times sdot) isin P(119867 times S)
For any 119899 ge 1 let 120587119899 119867 rarr 119867
119899= Span119890
1 1198902 119890
119899
be the orthogonal projection Consider SPDEs with Marko-vian switching on119867
119899
119889119883119899(119905) = [119860
119899119883119899(119905) + 119891
119899(119883119899(119905) 119903 (119905))] 119889119905
+ 119892119899(119883119899(119905) 119903 (119905)) 119889119882 (119905)
(13)
with initial data 119883119899(0) = 120587119899119909 = sum
119899
119894=1⟨119909 119890119894⟩119867119890119894 119909 isin 119867 Here
119860119899= 120587119899119860 119891119899= 120587119899119891 119892119899= 120587119899119892
Therefore we can observe that
119860119899119909 = 119860119909 119890
119905119860119899119909= 119890119905119860119909 ⟨119909 119891
119899⟩119867= ⟨119909 119891⟩
119867
⟨119909 119892119899⟩119867= ⟨119909 119892⟩
119867 forall119909 isin 119867
119899
(14)
By the property of the projection operator and (A2) we have
1003817100381710038171003817119860119899 (119909 minus 119910)10038171003817100381710038172
119867or1003817100381710038171003817119891119899 (119909 119895) minus 119891119899 (119910 119895)
10038171003817100381710038172
119867
or1003817100381710038171003817119892119899 (119909 119895) minus 119892119899 (119910 119895)
10038171003817100381710038172
HS
le 1205822
119899
1003817100381710038171003817(119909 minus 119910)10038171003817100381710038172
119867or1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)
10038171003817100381710038172
119867
or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS le (1205822
119899or 119871)1003817100381710038171003817(119909 minus 119910)
10038171003817100381710038172
119867
forall119909 119910 isin 119867119899 119895 isin S
(15)
Hence (13) admits a unique strong solution 119883119899(119905)119905ge0
on119867119899
(see [8])We now introduce an Euler-Maruyama based computa-
tionalmethodThemethodmakes use of the following lemma(see [15])
Lemma 6 Given Δ gt 0 then 119903(119896Δ) 119896 = 0 1 2 is adiscrete Markov chain with the one-step transition probabilitymatrix
119875 (Δ) = (119875119894119895(Δ))119873times119873= 119890ΔΓ (16)
Given a fixed step size Δ gt 0 and the one-step transitionprobability matrix 119875(Δ) in (16) the discrete Markov chain119903(119896Δ) 119896 = 0 1 2 can be simulated as follows let119903(0) = 119894
0 and compute a pseudorandom number 120585
1from the
uniform (0 1) distributionDefine
119903 (Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(0)119895(Δ)
le 1205851
lt
119894
sum119895=1
119875119903(0)119895(Δ)
119873
119873minus1
sum119895=1
119875119903(0)119895(Δ) le 120585
1
(17)
4 Abstract and Applied Analysis
where we set sum0119895=1119875119903(0)119895(Δ) = 0 as usual Having computed
119903(0) 119903(Δ) 119903(119896Δ) we can compute 119903((119896 + 1)Δ) by drawinga uniform (0 1) pseudorandom number 120585
119896+1and setting
119903 ((119896 + 1) Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(119896Δ)119895
(Δ)
le 120585119896+1lt
119894
sum119895=1
119875119903(119896Δ)119895
(Δ)
119873
119873minus1
sum119895=1
119875119903(119896Δ)119895
(Δ) le 120585119896+1
(18)
The procedure can be carried out repeatedly to obtain moretrajectories
We now define the Euler-Maruyama approximation for(13) For a stepsize Δ isin (0 1) the discrete approximation119884119899
(119896Δ) asymp 119883119899(119896Δ) is formed by simulating from 119884119899(0) =
120587119899119909 119903(0) = 119903
0 and
119884119899
((119896 + 1) Δ)
= 119890Δ119860119899 119884119899
(119896Δ) + 119891119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ
+119892119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ119882119896
(19)
where Δ119882119896= 119882((119896 + 1)Δ) minus 119882(119896Δ))
To carry out our analysis conveniently we give thecontinuous Euler-Maruyama approximation solution whichis defined by
119884119899(119905) = 119890
119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= 119890119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(20)
where lfloor119905rfloor = [119905Δ]Δ and [119905Δ] denotes the integer part of 119905Δand 119884119899(0) = 119884119899(0) = 120587
119899119909 and 119884119899(119896Δ) = 119884119899(119896Δ)
It is obvious that119884119899(119905) coincides with the discrete approx-imation solution at the gridpoints For any Borel set 119860 isinB(119867119899) 119909 isin 119867
119899 119894 119895 isin S let 119885
119899
(119896Δ) = (119884119899
(119896Δ) 119903(119896Δ))
P119899Δ((119909 119894) 119860 times 119895)
= P (119885119899
(Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
P119899Δ
119896((119909 119894) 119860 times 119895)
= P (119885119899
(119896Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
(21)
Following the argument of Theorem 5 in [13] we have thefollowing
Lemma 7 119885 119899(119896Δ)119896ge0
is a homogeneous Markov processwith the transition probability kernel P119899Δ((119909 119894) 119860 times 119895)
To highlight the initial value we will use notation119885119899(119909119894)
(119896Δ)
Definition 8 For a given stepsize Δ gt 0 119885119899(119909119894)
(119896Δ)119896ge0
issaid to have a stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times
S) if the 119896-step transition probability kernel P119899Δ119896((119909 119894) sdot times sdot)
converges weakly to 120587119899Δ(sdot times sdot) as 119896 rarr infin for every (119909 119894) isin119867119899times S that is
lim119896rarrinfin
119889L (119875119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (22)
We will establish our result of this paper in Section 3
Theorem 9 Under (A1)ndash(A3) for a given stepsize Δ gt 0and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has a uniquestationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
3 Stationary in Distribution ofNumerical Solutions
In this section we shall present some useful lemmas andproveTheorem 9 In what follows119862 gt 0 is a generic constantwhose values may change from line to line
For any initial value (119909 119894) let 119884119899119909119894(119905) be the continuousEuler-Maruyama solution of (20) and starting from (119909 119894) isin119867 times S Let 119883119909119894(119905) be the mild solution of (4) and startingfrom (119909 119894) isin 119867 times S
Lemma 10 Under (A1)ndash(A3) then
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119909119894(lfloor119905rfloor)10038171003817100381710038171003817
2
119867
le 3 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(23)
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119884119899119909119894(lfloor119905rfloor) = 119884119899(lfloor119905rfloor) From(20) we have
119884119899(lfloor119905rfloor) = 119890
lfloor119905rfloor119860120587119899119909 + int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(24)
Abstract and Applied Analysis 5
Thus
119884119899(119905) minus 119884
119899(lfloor119905rfloor)
= 119890(119905minuslfloor119905rfloor)119860
times (119890lfloor119905rfloor119860120587119899119909
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904) )
minus 119884119899(lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= (119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(25)
Then by theHolder inequality and the Ito isometrywe obtain
E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 3E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
(26)
From (A1) we have
E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
= E
1003817100381710038171003817100381710038171003817100381710038171003817
119899
sum
119894=1
(119890minus120588119894(119905minuslfloor119905rfloor)
minus 1) ⟨119884119899(lfloor119905rfloor) 119890
119894⟩119867119890119894
1003817100381710038171003817100381710038171003817100381710038171003817
2
119867
le (1 minus 119890minus120588119899(119905minuslfloor119905rfloor)
)2
E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 1205882
119899Δ2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
(27)
here we use the fundamental inequality 1 minus 119890minus119886 le 119886 119886 gt 0And by (8) it follows that
Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
le 2119871Δ (1 + E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(28)
Substituting (27) and (28) into (26) the desired assertion (23)follows
Lemma 11 Under (A1)ndash(A3) if Δ lt min1 13(1205882119899+ 2119871)
((4120572119901 + 120583)(8119902 + 41199021205882
119899119871+4119902119871 + 24119902 + 6119902119871(120588
2
119899+2119871)))
2
thenthere is a constant119862 gt 0 that depends on the initial value 119909 butis independent ofΔ such that the continuous Euler-Maruyamasolution of (20) has
sup119905ge0
E10038171003817100381710038171003817119884119899119909119894(119905)10038171003817100381710038171003817119867le 119862 (29)
where 119902 = max1le119894le119873
120582119894 119901 = min
1le119894le119873120582119894
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119903119894(119896Δ) = 119903(119896Δ) From (20) wehave the following differential form
119889119884119899(119905)
= 119860119884119899(119905) + 119890
(119905minuslfloor119905rfloor)119860119891119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119905
+ 119890(119905minuslfloor119905rfloor)119860
119892119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119882 (119905)
(30)
with 119884119899(0) = 120587119899119909
Let119881(119909 119894) = 120582119894 1199092
119867 By the generalised Ito formula for
any 120579 gt 0 we derive from (30) that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1205821198941199092
119867+ Eint
119905
0
119890120579119904120582119903(119904)
times 1205791003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ 2⟨119884
119899(119904) 119860119884
119899(119904)⟩119867
+ 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892119899 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
6 Abstract and Applied Analysis
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
(31)
By the fundamental transformation we obtain that
⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))⟩
119867
= ⟨119884119899(119905) 119891 (119884
119899(119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1) 119891 (119884119899 (119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119891 (119884119899(119905) 119903 (119905))) ⟩
119867
(32)
By Hold inequality we have
1003817100381710038171003817119892 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
=1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
minus (119892 (119884119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(33)
Then from (31) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2⟨119884119899(119904) 119891 (119884
119899(119904) 119903 (119904))⟩
119867
+1003817100381710038171003817119892 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus120583
2Eint119905
0
119890120579119904119884 (119904)
2
119867119889119904 + 120572
1int
119905
0
119890120579119904119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
(119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
= 1198691(119905) + 119869
2(119905) + 119869
3(119905) + 119869
4(119905)
(34)
By the elemental inequality 2119886119887 le (1198862120581)+1205811198872 119886 119887 isin R 120581 gt0 and (8) (27) we obtain that for Δ lt 1
1198692(119905) le Eint
119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times 119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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4 Abstract and Applied Analysis
where we set sum0119895=1119875119903(0)119895(Δ) = 0 as usual Having computed
119903(0) 119903(Δ) 119903(119896Δ) we can compute 119903((119896 + 1)Δ) by drawinga uniform (0 1) pseudorandom number 120585
119896+1and setting
119903 ((119896 + 1) Δ)
=
119894 119894 isin S minus 119873
such that119894minus1
sum119895=1
119875119903(119896Δ)119895
(Δ)
le 120585119896+1lt
119894
sum119895=1
119875119903(119896Δ)119895
(Δ)
119873
119873minus1
sum119895=1
119875119903(119896Δ)119895
(Δ) le 120585119896+1
(18)
The procedure can be carried out repeatedly to obtain moretrajectories
We now define the Euler-Maruyama approximation for(13) For a stepsize Δ isin (0 1) the discrete approximation119884119899
(119896Δ) asymp 119883119899(119896Δ) is formed by simulating from 119884119899(0) =
120587119899119909 119903(0) = 119903
0 and
119884119899
((119896 + 1) Δ)
= 119890Δ119860119899 119884119899
(119896Δ) + 119891119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ
+119892119899(119884119899
(119896Δ) 119903 (119896Δ)) Δ119882119896
(19)
where Δ119882119896= 119882((119896 + 1)Δ) minus 119882(119896Δ))
To carry out our analysis conveniently we give thecontinuous Euler-Maruyama approximation solution whichis defined by
119884119899(119905) = 119890
119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119899119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= 119890119905119860119899120587119899119909 + int
119905
0
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
0
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(20)
where lfloor119905rfloor = [119905Δ]Δ and [119905Δ] denotes the integer part of 119905Δand 119884119899(0) = 119884119899(0) = 120587
119899119909 and 119884119899(119896Δ) = 119884119899(119896Δ)
It is obvious that119884119899(119905) coincides with the discrete approx-imation solution at the gridpoints For any Borel set 119860 isinB(119867119899) 119909 isin 119867
119899 119894 119895 isin S let 119885
119899
(119896Δ) = (119884119899
(119896Δ) 119903(119896Δ))
P119899Δ((119909 119894) 119860 times 119895)
= P (119885119899
(Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
P119899Δ
119896((119909 119894) 119860 times 119895)
= P (119885119899
(119896Δ) isin 119860 times 119895 | 119885119899
(0) = (119909 119894))
(21)
Following the argument of Theorem 5 in [13] we have thefollowing
Lemma 7 119885 119899(119896Δ)119896ge0
is a homogeneous Markov processwith the transition probability kernel P119899Δ((119909 119894) 119860 times 119895)
To highlight the initial value we will use notation119885119899(119909119894)
(119896Δ)
Definition 8 For a given stepsize Δ gt 0 119885119899(119909119894)
(119896Δ)119896ge0
issaid to have a stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times
S) if the 119896-step transition probability kernel P119899Δ119896((119909 119894) sdot times sdot)
converges weakly to 120587119899Δ(sdot times sdot) as 119896 rarr infin for every (119909 119894) isin119867119899times S that is
lim119896rarrinfin
119889L (119875119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (22)
We will establish our result of this paper in Section 3
Theorem 9 Under (A1)ndash(A3) for a given stepsize Δ gt 0and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has a uniquestationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
3 Stationary in Distribution ofNumerical Solutions
In this section we shall present some useful lemmas andproveTheorem 9 In what follows119862 gt 0 is a generic constantwhose values may change from line to line
For any initial value (119909 119894) let 119884119899119909119894(119905) be the continuousEuler-Maruyama solution of (20) and starting from (119909 119894) isin119867 times S Let 119883119909119894(119905) be the mild solution of (4) and startingfrom (119909 119894) isin 119867 times S
Lemma 10 Under (A1)ndash(A3) then
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119909119894(lfloor119905rfloor)10038171003817100381710038171003817
2
119867
le 3 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(23)
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119884119899119909119894(lfloor119905rfloor) = 119884119899(lfloor119905rfloor) From(20) we have
119884119899(lfloor119905rfloor) = 119890
lfloor119905rfloor119860120587119899119909 + int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(24)
Abstract and Applied Analysis 5
Thus
119884119899(119905) minus 119884
119899(lfloor119905rfloor)
= 119890(119905minuslfloor119905rfloor)119860
times (119890lfloor119905rfloor119860120587119899119909
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904) )
minus 119884119899(lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= (119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(25)
Then by theHolder inequality and the Ito isometrywe obtain
E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 3E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
(26)
From (A1) we have
E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
= E
1003817100381710038171003817100381710038171003817100381710038171003817
119899
sum
119894=1
(119890minus120588119894(119905minuslfloor119905rfloor)
minus 1) ⟨119884119899(lfloor119905rfloor) 119890
119894⟩119867119890119894
1003817100381710038171003817100381710038171003817100381710038171003817
2
119867
le (1 minus 119890minus120588119899(119905minuslfloor119905rfloor)
)2
E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 1205882
119899Δ2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
(27)
here we use the fundamental inequality 1 minus 119890minus119886 le 119886 119886 gt 0And by (8) it follows that
Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
le 2119871Δ (1 + E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(28)
Substituting (27) and (28) into (26) the desired assertion (23)follows
Lemma 11 Under (A1)ndash(A3) if Δ lt min1 13(1205882119899+ 2119871)
((4120572119901 + 120583)(8119902 + 41199021205882
119899119871+4119902119871 + 24119902 + 6119902119871(120588
2
119899+2119871)))
2
thenthere is a constant119862 gt 0 that depends on the initial value 119909 butis independent ofΔ such that the continuous Euler-Maruyamasolution of (20) has
sup119905ge0
E10038171003817100381710038171003817119884119899119909119894(119905)10038171003817100381710038171003817119867le 119862 (29)
where 119902 = max1le119894le119873
120582119894 119901 = min
1le119894le119873120582119894
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119903119894(119896Δ) = 119903(119896Δ) From (20) wehave the following differential form
119889119884119899(119905)
= 119860119884119899(119905) + 119890
(119905minuslfloor119905rfloor)119860119891119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119905
+ 119890(119905minuslfloor119905rfloor)119860
119892119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119882 (119905)
(30)
with 119884119899(0) = 120587119899119909
Let119881(119909 119894) = 120582119894 1199092
119867 By the generalised Ito formula for
any 120579 gt 0 we derive from (30) that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1205821198941199092
119867+ Eint
119905
0
119890120579119904120582119903(119904)
times 1205791003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ 2⟨119884
119899(119904) 119860119884
119899(119904)⟩119867
+ 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892119899 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
6 Abstract and Applied Analysis
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
(31)
By the fundamental transformation we obtain that
⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))⟩
119867
= ⟨119884119899(119905) 119891 (119884
119899(119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1) 119891 (119884119899 (119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119891 (119884119899(119905) 119903 (119905))) ⟩
119867
(32)
By Hold inequality we have
1003817100381710038171003817119892 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
=1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
minus (119892 (119884119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(33)
Then from (31) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2⟨119884119899(119904) 119891 (119884
119899(119904) 119903 (119904))⟩
119867
+1003817100381710038171003817119892 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus120583
2Eint119905
0
119890120579119904119884 (119904)
2
119867119889119904 + 120572
1int
119905
0
119890120579119904119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
(119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
= 1198691(119905) + 119869
2(119905) + 119869
3(119905) + 119869
4(119905)
(34)
By the elemental inequality 2119886119887 le (1198862120581)+1205811198872 119886 119887 isin R 120581 gt0 and (8) (27) we obtain that for Δ lt 1
1198692(119905) le Eint
119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times 119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
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Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
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Mathematical PhysicsAdvances in
Complex AnalysisJournal of
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OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
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Operations ResearchAdvances in
Journal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Decision SciencesAdvances in
Discrete MathematicsJournal of
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Volume 2014
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Stochastic AnalysisInternational Journal of
Abstract and Applied Analysis 5
Thus
119884119899(119905) minus 119884
119899(lfloor119905rfloor)
= 119890(119905minuslfloor119905rfloor)119860
times (119890lfloor119905rfloor119860120587119899119909
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
lfloor119905rfloor
0
119890(lfloor119905rfloorminuslfloor119904rfloor)119860
times 119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904) )
minus 119884119899(lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
= (119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
119892119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)) 119889119882 (119904)
(25)
Then by theHolder inequality and the Ito isometrywe obtain
E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 3E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
(26)
From (A1) we have
E10038171003817100381710038171003817(119890(119905minuslfloor119905rfloor)119860
minus 1) 119884119899 (lfloor119905rfloor)100381710038171003817100381710038172
119867
= E
1003817100381710038171003817100381710038171003817100381710038171003817
119899
sum
119894=1
(119890minus120588119894(119905minuslfloor119905rfloor)
minus 1) ⟨119884119899(lfloor119905rfloor) 119890
119894⟩119867119890119894
1003817100381710038171003817100381710038171003817100381710038171003817
2
119867
le (1 minus 119890minus120588119899(119905minuslfloor119905rfloor)
)2
E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 1205882
119899Δ2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
(27)
here we use the fundamental inequality 1 minus 119890minus119886 le 119886 119886 gt 0And by (8) it follows that
Eint119905
lfloor119905rfloor
1003817100381710038171003817119891119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867119889119904
+ Eint119905
lfloor119905rfloor
1003817100381710038171003817119892119899 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS119889119904
le 2119871Δ (1 + E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
(28)
Substituting (27) and (28) into (26) the desired assertion (23)follows
Lemma 11 Under (A1)ndash(A3) if Δ lt min1 13(1205882119899+ 2119871)
((4120572119901 + 120583)(8119902 + 41199021205882
119899119871+4119902119871 + 24119902 + 6119902119871(120588
2
119899+2119871)))
2
thenthere is a constant119862 gt 0 that depends on the initial value 119909 butis independent ofΔ such that the continuous Euler-Maruyamasolution of (20) has
sup119905ge0
E10038171003817100381710038171003817119884119899119909119894(119905)10038171003817100381710038171003817119867le 119862 (29)
where 119902 = max1le119894le119873
120582119894 119901 = min
1le119894le119873120582119894
Proof Write 119884119899119909119894(119905) = 119884119899(119905) 119903119894(119896Δ) = 119903(119896Δ) From (20) wehave the following differential form
119889119884119899(119905)
= 119860119884119899(119905) + 119890
(119905minuslfloor119905rfloor)119860119891119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119905
+ 119890(119905minuslfloor119905rfloor)119860
119892119899(119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) 119889119882 (119905)
(30)
with 119884119899(0) = 120587119899119909
Let119881(119909 119894) = 120582119894 1199092
119867 By the generalised Ito formula for
any 120579 gt 0 we derive from (30) that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1205821198941199092
119867+ Eint
119905
0
119890120579119904120582119903(119904)
times 1205791003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ 2⟨119884
119899(119904) 119860119884
119899(119904)⟩119867
+ 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891119899(119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892119899 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
6 Abstract and Applied Analysis
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
(31)
By the fundamental transformation we obtain that
⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))⟩
119867
= ⟨119884119899(119905) 119891 (119884
119899(119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1) 119891 (119884119899 (119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119891 (119884119899(119905) 119903 (119905))) ⟩
119867
(32)
By Hold inequality we have
1003817100381710038171003817119892 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
=1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
minus (119892 (119884119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(33)
Then from (31) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2⟨119884119899(119904) 119891 (119884
119899(119904) 119903 (119904))⟩
119867
+1003817100381710038171003817119892 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus120583
2Eint119905
0
119890120579119904119884 (119904)
2
119867119889119904 + 120572
1int
119905
0
119890120579119904119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
(119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
= 1198691(119905) + 119869
2(119905) + 119869
3(119905) + 119869
4(119905)
(34)
By the elemental inequality 2119886119887 le (1198862120581)+1205811198872 119886 119887 isin R 120581 gt0 and (8) (27) we obtain that for Δ lt 1
1198692(119905) le Eint
119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times 119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Stochastic AnalysisInternational Journal of
6 Abstract and Applied Analysis
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))⟩
119867
+1003817100381710038171003817119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
(31)
By the fundamental transformation we obtain that
⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))⟩
119867
= ⟨119884119899(119905) 119891 (119884
119899(119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1) 119891 (119884119899 (119905) 119903 (119905))⟩
119867
+ ⟨119884119899(119905) 119890(119905minuslfloor119905rfloor)119860
(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119891 (119884119899(119905) 119903 (119905))) ⟩
119867
(32)
By Hold inequality we have
1003817100381710038171003817119892 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
=1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
minus (119892 (119884119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119905) 119903 (119905)) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(33)
Then from (31) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2⟨119884119899(119904) 119891 (119884
119899(119904) 119903 (119904))⟩
119867
+1003817100381710038171003817119892 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
le 1199021199092
119867+ 120579119902Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
minus120583
2Eint119905
0
119890120579119904119884 (119904)
2
119867119889119904 + 120572
1int
119905
0
119890120579119904119889119904
+ Eint119905
0
119890120579119904120582119903(119904)
times 2⟨119884119899(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1) 119891 (119884119899 (119904) 119903 (119904))⟩
119867
+ 2 ⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
(119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867
+ Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS + (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119899(119904) 119903 (119904))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
10038171003817100381710038172
HS 119889119904
= 1198691(119905) + 119869
2(119905) + 119869
3(119905) + 119869
4(119905)
(34)
By the elemental inequality 2119886119887 le (1198862120581)+1205811198872 119886 119887 isin R 120581 gt0 and (8) (27) we obtain that for Δ lt 1
1198692(119905) le Eint
119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times 119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Discrete Dynamics in Nature and Society
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Discrete MathematicsJournal of
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Volume 2014
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Stochastic AnalysisInternational Journal of
Abstract and Applied Analysis 7
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δminus121205882
119899Δ2119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ121205882
119899119871)
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δ121205882
119899119871 119889119904
(35)
By (A2) and (8) we have
1003817100381710038171003817(119891 (119884119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119899(lfloor119905rfloor) 119903 (119905)))
10038171003817100381710038172
119867
+ 21003817100381710038171003817(119891 (119884
119899(lfloor119905rfloor) 119903 (119905)) minus 119891 (119884
119899(119905) 119903 (119905)))
10038171003817100381710038172
119867
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(36)
Similarly we have
1003817100381710038171003817119892 (119884119899(119905) 119903 (119905))) minus 119892 (119884
119899(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le 8119871 (1 +1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
+ 21198711003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867
(37)
Thus we obtain from (36) that
1198693(119905)
le 2Eint119905
0
119890120579119904120582119903(119904)⟨119884119899(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))) ⟩
119867119889119904
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + Δ
minus1210038171003817100381710038171003817119890(119904minuslfloor119904rfloor)11986010038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119899(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867+ Δminus128119871
times (1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(38)
By Markov property we compute
E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
]
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) 119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)])
= E (E [(1 + 119884 (lfloor119905rfloor)2
119867) | 119903 (lfloor119905rfloor)])
times E [119868119903(119905) = 119903(lfloor119905rfloor)
| 119903 (lfloor119905rfloor)]
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
P (119903 (119905) = 119894 | 119903 (lfloor119905rfloor) = 119894)
= E (1 + 119884 (lfloor119905rfloor)2
119867)sum
119894isinS
119868119903(lfloor119905rfloor)=119894
times sum
119895 = 119894
(120574119894119895(119905 minus lfloor119905rfloor) + 119900 (119905 minus lfloor119905rfloor))
= E (1 + 119884 (lfloor119905rfloor)2
119867) (max119894isinS(minus120574119894119894) Δ + 119900 (Δ))sum
119894isinS
119868119903(lfloor119905rfloor)=119894
le ΔE (1 + 119884 (lfloor119905rfloor)2
119867)
(39)
where = 119873[1 +max1le119894le119873
(minus120574119894119894)] Substituting (39) into (38)
gives
1198693(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867
+2Δminus121198711003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
+ 119902int
119905
0
8119890120579119904Δ12119871E (1 + 119884 (lfloor119904rfloor)
2
119867) 119889119904
(40)
Furthermore due to (37) and (39) we have
1198694(119905)
= Eint119905
0
119890120579119904120582119903(119904)
times Δ121003817100381710038171003817119892 (119884
119899(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)1003817100381710038171003817119892 (119884
119899(119904) 119903 (119904)))
minus119892 (119884119899(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Differential EquationsInternational Journal of
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Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Discrete Dynamics in Nature and Society
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Volume 2014
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Stochastic AnalysisInternational Journal of
8 Abstract and Applied Analysis
le 119902Eint119905
0
119890120579119904Δ12119871 (1 +
1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904 + 119902 (1 + Δ
minus12)
times int
119905
0
1198901205791199048119871 (1 +
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
le 119902Δ12119871Eint119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 16119902Δ12119871int
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867) 119889119904
+ 2119871119902 (1 + Δminus12)int
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(41)
On the other hand by Lemma 10 when 3(1205882119899+ 2119871)Δ le 1 we
have
E1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867
le 2E1003817100381710038171003817119884119899(119905) minus 119884
119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 6 (1205882
119899+ 2119871)Δ (1 + E
1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867)
+ 2E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867
le 4E1003817100381710038171003817119884119899(lfloor119905rfloor)10038171003817100381710038172
119867+ 2
(42)
Putting (35) (40) and (41) into (34) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 1199021205882
119899Δ12119871
+24119902Δ12 119871 + 119902Δ
12119871] 119889119904
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus
120583
2+ 119902Δ12(2 + 120588
2
119899119871) + 119902Δ
12119871]
times1003817100381710038171003817119884119899(119904)10038171003817100381710038172
119867119889119904 + 24119902Δ
12 119871E
times int
119905
0
1198901205791199041003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ (4119902Δminus12119871 + 2119902119871)Eint
119905
0
1198901205791199041003817100381710038171003817119884119899(119904) minus 119884
119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(43)
By Lemma 10 and the inequality (42) we obtain that
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119899(119905)10038171003817100381710038172
119867)
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583
+ 31199021205882
119899Δ12119871 + 24119902Δ
12 119871
+3119902Δ12119871 + 4119902Δ
12] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+4119902Δ12119871 + 24119902Δ
12 119871]1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
+ 6119902119871Δ12(1205882
119899+ 2119871)Eint
119905
0
119890120579119904(1 +1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867) 119889119904
le 1199021199092
119867+ int
119905
0
119890120579119904[1205721+ 2119902120579 minus 4120572119901 minus 120583 + 3119902120588
2
119899Δ12119871
+ 24119902Δ12 119871 + 3119902Δ
12119871 + 4119902Δ
12
+6119902119871Δ12(1205882
119899+ 2119871)] 119889119904
+ int
119905
0
119890120579119904[4119902120579 minus 8120572119901 minus 2120583 + 4119902Δ
12(2 + 120588
2
119899119871)
+ 4119902Δ12119871 + 24119902Δ
12 119871
+6119902119871Δ12(1205882
119899+ 2119871)]
1003817100381710038171003817119884119899(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(44)
Let 120579 = (4120572119901+120583)4119902 for Δ lt ((4120572119901+120583)(8119902+41199021205882119899119871+4119902119871+
24119902 + 6119902119871(1205882
119899+ 2119871)))
2 then
119901119890120579119905E (119884 (119905)
2
119867) le 119902119909
2
119867+ int
119905
0
119890120579119904[1205721+4120572119901 + 120583
2] 119889119904
(45)
That is
sup119905ge0
E (119884 (119905)2
119867) le 119862 (46)
Lemma 12 Let (A1)ndash(A3) hold If Δ lt min1 118(1205882119899+
2119871) ((2120572119901 + 120583)(4119902 + 2119902119871 + 21199021205882
119899119871 + 12119902119871))
2 then
lim119905rarrinfin
E10038171003817100381710038171003817119884119899119909119894(119905) minus 119884
119899119910119894(119905)10038171003817100381710038171003817
2
119867= 0 119906119899119894119891119900119903119898119897119910 119891119900119903 119909 119910 isin 119880
(47)
where 119880 is a bounded subset of119867119899
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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Volume 2014
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Stochastic AnalysisInternational Journal of
Abstract and Applied Analysis 9
Proof Write 119884119899119909119894(119905) = 119884119909(119905) 119884119899119910119894(119905) = 119884119910(119905) 119903119894(119896Δ) =119903(119896Δ) From (20) it is easy to show that
(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
= (119884119909(119905) minus 119884
119909(lfloor119905rfloor)) minus (119884
119910(119905) minus 119884
119910(lfloor119905rfloor))
= (119890(119905minuslfloor119905rfloor)119860
minus 1) (119884119909 (lfloor119905rfloor) minus 119884119910 (lfloor119905rfloor))
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119904
+ int
119905
lfloor119905rfloor
119890(119905minuslfloor119904rfloor)119860
(119892119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) 119889119882 (119904)
(48)
By using the argument of Lemma 10 we derive that if Δ lt 1
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le 3 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
(49)
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867
= E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905)) minus (119884
119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
+ (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
le (1 + 2)E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))
minus (119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ (1 +1
2)E1003817100381710038171003817119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor)10038171003817100381710038172
119867
le 9 (1205882
119899+ 2119871)ΔE
1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
+ 15E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867
(50)
If Δ lt 118(1205882119899+ 2119871) then
E1003817100381710038171003817(119884119909(119905) minus 119884
119910(119905))10038171003817100381710038172
119867le 2E1003817100381710038171003817(119884119909(lfloor119905rfloor) minus 119884
119910(lfloor119905rfloor))
10038171003817100381710038172
119867 (51)
Using (30) and the generalised Ito formula for any 120579 gt 0 wehave
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 120582119894
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
+ Eint119905
0
119890120579119904120582119903(119904)1205791003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904)
119860119884119909(119904) minus 119884
119910(119904)⟩119867
+ 2 ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891119899(119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))⟩
119867
+1003817100381710038171003817119892119899 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892119899(119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ 119902120579Eint
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
minus 2120572119901Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)2 ⟨119884
119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))) ⟩
119867
+1003817100381710038171003817119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119892 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
HS 119889119904
+ Eint119905
0
119890120579119904
119873
sum
119897=1
120574119903(119904)119897120582119897
1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(52)
By the fundamental transformation we obtain that
⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))) ⟩
119867
= ⟨119884119909(119905) minus 119884
119910(119905) 119891 (119884
119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) (119890
(119905minuslfloor119905rfloor)119860minus 1)
times (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
+ ⟨119884119909(119905) minus 119884
119910(119905) 119890(119905minuslfloor119905rfloor)119860
times (119891 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119891 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
minus (119891 (119884119909(119905) 119903 (119905)) minus 119891 (119884
119910(119905) 119903 (119905))) ⟩
119867
(53)
By the Hold inequality we have
1003817100381710038171003817119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor)) minus 119892 (119884
119910(lfloor119905rfloor) 119903 (lfloor119905rfloor))
10038171003817100381710038172
HS
le (1 + Δ12)1003817100381710038171003817119892 (119884119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905))
10038171003817100381710038172
HS
10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
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10 Abstract and Applied Analysis
+ (1 + Δminus12)1003817100381710038171003817(119892 (119884
119909(119905) 119903 (119905)) minus 119892 (119884
119910(119905) 119903 (119905)))
minus (119892 (119884119909(lfloor119905rfloor) 119903 (lfloor119905rfloor))
minus119892 (119884119910(lfloor119905rfloor) 119903 (lfloor119905rfloor)))
10038171003817100381710038172
HS
(54)
Then from (52) and (A3) we have
119890120579119905E (120582119903(119905)
1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ (119902120579 minus 2120572119901 minus 120583)E
times int
119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) (119890
(119904minuslfloor119904rfloor)119860minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904))) ⟩
119867119889119904
+ 2Eint119905
0
119890120579119904120582119903(119904)
times ⟨119884119909(119904) minus 119884
119910(119904) 119890(119904minuslfloor119904rfloor)119860
times (119891 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor)))
minus (119891 (119884119909(119904) 119903 (119904))
minus119891 (119884119910(119904) 119903 (119904)))⟩
119867119889119904
+ Eint119905
0
119890120579119904120582119903(119904)Δ12 1003817100381710038171003817119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904))
10038171003817100381710038172
HS
+ (1 + Δminus12)
times1003817100381710038171003817(119892 (119884
119909(119904) 119903 (119904))
minus119892 (119884119910(119904) 119903 (119904)))
minus (119892 (119884119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119892 (119884119910(lfloor119904rfloor)
119903 (lfloor119904rfloor) ) )10038171003817100381710038172
HS 119889119904
= 1198661(119905) + 119866
2(119905) + 119866
3(119905) + 119866
4(119905)
(55)
By (A2) and (27) we have for Δ lt 1
1198662(119905)
le Eint119905
0
119890120579119904120582119903(119904)Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus12 10038171003817100381710038171003817
(119890(119904minuslfloor119904rfloor)119860
minus 1)
times (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le Eint119905
0
119890120579119904120582119903(119904)(Δ12+ Δ321205882
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
le 119902Eint119905
0
119890120579119904Δ12(1 + 120588
2
119899119871)1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
(56)
It is easy to show that
1198663(119905)
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ Δminus1210038171003817100381710038171003817(119890(119904minuslfloor119904rfloor)119860
)10038171003817100381710038171003817
2
times1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus 119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus (119891 (119884119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867 119889119904
le 119902Eint119905
0
119890120579119904Δ121003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904 + 119866
3(119905)
(57)
By (39) we have
1198663(119905)
le 2119902Δminus12
Eint119905
0
119890120579119904[1003817100381710038171003817119891 (119884
119909(lfloor119904rfloor) 119903 (lfloor119904rfloor))
minus119891 (119884119910(lfloor119904rfloor) 119903 (lfloor119904rfloor))
10038171003817100381710038172
119867
+1003817100381710038171003817(119891 (119884
119909(119904) 119903 (119904))
minus119884119910(119904) 119903 (119904))
10038171003817100381710038172
119867]
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902Δminus12119871Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867
times 119868119903(119904) = 119903(lfloor119904rfloor)
119889119904
le 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(58)
Therefore we obtain that
1198663(119905) le 119902Δ
12Eint119905
0
1198901205791199041003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ 4119902119871Δ12
Eint119905
0
1198901205791199041003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(59)
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
Submit your manuscripts athttpwwwhindawicom
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
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Stochastic AnalysisInternational Journal of
Abstract and Applied Analysis 11
On the other hand using the similar argument of (58) wehave
1198664(119905) le 119902Eint
119905
0
119890120579119904Δ121198711003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867
+ (1 + Δminus12) 4119871Δ
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867 119889119904
(60)
Hence we have
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
+ Eint119905
0
119890120579119904[119902120579 minus 2120572119901 minus 120583 + 119902 (1 + 120588
2
119899119871)Δ12
+119902Δ12+ 119902119871Δ
12]1003817100381710038171003817119884119909(119904) minus 119884
119910(119904)10038171003817100381710038172
119867119889119904
+ Eint119905
0
119890120579119904[4119902119871Δ
12+ (Δ12+ Δ) 4119902119871]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(61)
By (50) we obtain that
119901119890120579119905E (1003817100381710038171003817119884119909(119905) minus 119884
119910(119905)10038171003817100381710038172
119867)
le 1199021003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867+ Eint
119905
0
119890120579119904[2119902120579 minus 4120572119901 minus 2120583
+ 4119902Δ12+ 2119902119871Δ
12
+21199021205882
119899119871Δ12+ 12119902119871Δ
12]
times1003817100381710038171003817119884119909(lfloor119904rfloor) minus 119884
119910(lfloor119904rfloor)10038171003817100381710038172
119867119889119904
(62)
Let 120579 = (2120572119901+120583)2119902 for Δ lt ((2120572119901+120583)(4119902+ 2119902119871+21199021205882119899119871+
12119902119871))2 then the desired assertion (47) follows
We can now easily prove our main result
Proof of Theorem 9 Since 119867119899
is finite-dimensional byLemma 31 in [12] we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((119910 119894) sdot times sdot)) = 0 (63)
uniformly in 119909 119910 isin 119867119899 119894 119895 isin S
By Lemma 7 there exists 120587119899Δ(sdot times sdot) isin P(119867119899times S) such
that
lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0 (64)
By the triangle inequality (63) and (64) we have
lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) 120587
119899Δ(sdot times sdot))
le lim119896rarrinfin
119889L (P119899Δ
119896((119909 119894) sdot times sdot) P
119899Δ
119896((0 1) sdot times sdot))
+ lim119896rarrinfin
119889L (P119899Δ
119896((0 1) sdot times sdot) 120587
119899Δ(sdot times sdot)) = 0
(65)
4 Corollary and Example
In this section we give a criterion based119872-matrices whichcan be verified easily in applications(A4) For each 119895 isin S there exists a pair of constants 120573
119895and
120575119895such that for 119909 119910 isin 119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867le 120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(66)
MoreoverA = minus diag(21205731+1205751 2120573
119873+120575119873) minus Γ is
a nonsingular119872-matrix [8]
Corollary 13 Under (A1) (A2) and (A4) for a given stepsizeΔ gt 0 and arbitrary 119909 isin 119867
119899 119894 isin S 119885
119899(119909119894)
(119896Δ)119896ge0
has aunique stationary distribution 120587119899Δ(sdot times sdot) isin P(119867
119899times S)
Proof In fact we only need to prove that (A3) holdsBy (A4) there exists (120582
1 1205822 120582
119873)119879gt 0 such that
(1199021 1199022 119902
119873)119879= A(120582
1 1205822 120582
119873)119879gt 0
Set 120583 = min1le119895le119873
119902119895 by (66) we have
2120582119895⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩
119867
+ 120582119895
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
le 2120582119895120573119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+ 120575119895120582119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867+
119873
sum
119897=1
120574119895119897120582119897
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
= (2120582119895120573119895+ 120575119895120582119895+
119873
sum
119897=1
120574119895119897120582119897)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
= minus119902119895
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867le minus1205831003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(67)
In the following we give an example to illustrate theCorollary 13
Example 14 Consider
119889119883 (119905 120585) = [1205972
1205971205852119883(119905 120585) + 119861 (119903 (119905))119883 (119905 120585)] 119889119905
+ 119892 (119883 (119905 120585) 119903 (119905)) 119889119882 (119905) 0 lt 120585 lt 120587 119905 ge 0
(68)
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
12 Abstract and Applied Analysis
We take 119867 = 1198712(0 120587) and 119860 = 12059721205971205852 with domainD(119860) = 1198672(0 120587) cap1198671
0(0 120587) then 119860 is a self-adjoint negative
operator For the eigenbasis 119890119896(120585) = (2120587)
12 sin(119896120585) 120585 isin[0 120587] 119860119890
119896= minus1198962119890119896 119896 isin N It is easy to show that
1003817100381710038171003817100381711989011990511986011990910038171003817100381710038171003817
2
119867=
infin
sum
119894=1
119890minus21198962
119905⟨119909 119890119894⟩2
119867le 119890minus2119905
infin
sum
119894=1
⟨119909 119890119894⟩2
119867 (69)
This further gives that1003817100381710038171003817100381711989011990511986010038171003817100381710038171003817le 119890minus119905 (70)
where 120572 = 1 thus (A1) holdsLet 119882(119905) be a scalar Brownian motion let 119903(119905) be a
continuous-time Markov chain values in S = 1 2 with thegenerator
Γ = (minus2 2
1 minus1)
119861 (1) = 1198611= (minus03 minus01
minus02 minus02)
119861 (2) = 1198612= (minus04 minus02
minus03 minus02)
(71)
Then 120582max(119861119879
11198611) = 01706 120582max(119861
119879
21198612) = 03286
Moreover 119892 satisfies
1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)10038171003817100381710038172
HS le 1205751198951003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867 (72)
where 1205751= 01 120575
2= 006
Defining 119891(119909 119895) = 119861(119895)119909 then
1003817100381710038171003817119891 (119909 119895) minus 119891 (119910 119895)10038171003817100381710038172
HS or1003817100381710038171003817119892 (119909 119895) minus 119892 (119910 119895)
10038171003817100381710038172
HS
le (120582max (119861119879
119895119861119895) or 120575119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867lt 033
1003817100381710038171003817119909 minus 11991010038171003817100381710038172
119867
⟨119909 minus 119910 119891 (119909 119895) minus 119891 (119910 119895)⟩119867
le1
2⟨119909 minus 119910 (119861
119879
119895+ 119861119895) (119909 minus 119910)⟩
119867
le1
2120582max (119861
119879
119895+ 119861119895)1003817100381710038171003817119909 minus 119910
10038171003817100381710038172
119867
(73)
It is easy to compute
1205731=1
2120582max (119861
119879
1+ 1198611) = minus00919
1205732=1
2120582max (119861
119879
2+ 1198612) = minus003075
(74)
So the matrixA becomes
A = diag (00838 00015) minus Γ = (20838 minus2
minus1 10015) (75)
It is easy to see that A is a nonsingular119872-matrix Thus(A4) holds By Corollary 13 we can conclude that (68) has aunique stationary distribution 120587119899Δ(sdot times sdot)
Acknowledgment
This work is partially supported by the National NaturalScience Foundation of China under Grants 61134012 and11271146
References
[1] G Da Prato and J Zabczyk Stochastic Equations in Infinite-Dimensions CambridgeUniversity Press CambridgeUK 1992
[2] A Debussche ldquoWeak approximation of stochastic partial differ-ential equations the nonlinear caserdquoMathematics of Computa-tion vol 80 no 273 pp 89ndash117 2011
[3] I Gyongy and A Millet ldquoRate of convergence of space timeapproximations for stochastic evolution equationsrdquo PotentialAnalysis vol 30 no 1 pp 29ndash64 2009
[4] A Jentzen and P E Kloeden Taylor Approximations forStochastic Partial Differential Equations CBMS-NSF RegionalConference Series in Applied Mathematics 2011
[5] T Shardlow ldquoNumerical methods for stochastic parabolicPDEsrdquoNumerical Functional Analysis andOptimization vol 20no 1-2 pp 121ndash145 1999
[6] M Athans ldquoCommand and control (C2) theory a challenge tocontrol sciencerdquo IEEE Transactions on Automatic Control vol32 no 4 pp 286ndash293 1987
[7] D J Higham X Mao and C Yuan ldquoPreserving exponentialmean-square stability in the simulation of hybrid stochasticdifferential equationsrdquo Numerische Mathematik vol 108 no 2pp 295ndash325 2007
[8] X Mao and C Yuan Stochastic Differential Equations withMarkovian Switching Imperial College London UK 2006
[9] M Mariton Jump Linear Systems in Automatic Control MarcelDekker 1990
[10] J Bao Z Hou and C Yuan ldquoStability in distribution of mildsolutions to stochastic partial differential equationsrdquo Proceed-ings of the American Mathematical Society vol 138 no 6 pp2169ndash2180 2010
[11] J Bao and C Yuan ldquoNumerical approximation of stationarydistribution for SPDEsrdquo httparxivorgabs13031600
[12] X Mao C Yuan and G Yin ldquoNumerical method for stationarydistribution of stochastic differential equations withMarkovianswitchingrdquo Journal of Computational and Applied Mathematicsvol 174 no 1 pp 1ndash27 2005
[13] C Yuan and X Mao ldquoStationary distributions of Euler-Maruyama-type stochastic difference equations with Marko-vian switching and their convergencerdquo Journal of DifferenceEquations and Applications vol 11 no 1 pp 29ndash48 2005
[14] C Yuan and X Mao ldquoAsymptotic stability in distribution ofstochastic differential equations with Markovian switchingrdquoStochastic Processes and their Applications vol 103 no 2 pp277ndash291 2003
[15] W J Anderson Continuous-Time Markov Chains SpringerNew York NY USA 1991
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of