Jun 2015, Volume 10 Issue 4
    

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  • SURVEY ARTICLE
    Shizan FANG,Vincent NOLOT

    We will give a survey on results concerning Girsanov transformations, transportation cost inequalities, convexity of entropy, and optimal transport maps on some infinite dimensional spaces. Some open Problems will be arisen.

  • RESEARCH ARTICLE
    Anyue CHEN,Xiliu LI,HoMing KU

    We use a new approach to consider the extinction properties of the Markov branching process with immigration and migration recently discussed by Li and Liu [Sci. China Math., 2011, 54: 1043–1062]. Some much better explicit expressions are obtained for the extinction probabilities of the subtle super-interacting case.

  • RESEARCH ARTICLE
    Xin CHEN,Jian WANG

    Let (Xt)t≥0 be a symmetric strong Markov process generated by non-local regular Dirichlet form (D, D(D)) as follows:

    D(f,g)=?d?d(f(x)-f(y))(g(x)-g(y))J(x,y)dxdy,?f,gD(D),

    where J(x, y) is a strictly positive and symmetric measurable function on ?d×?d. We study the intrinsic hypercontractivity, intrinsic supercontractivity, and intrinsic ultracontractivity for the Feynman-Kac semigroup

    TtV(f)(x)=Ex(exp?(-0tV(Xs)ds)f(Xt)),?x?d,fL2(?d;dx).

    In particular, we prove that for J(x,y)|x-y|-d-al{|x-y|1}+e-|x-y|l{|x-y|>1} with α ∈(0, 2) and V(x)=|x|λ with λ>0, (TtV)t0 is intrinsically ultracontractive if and only if λ>1; and that for symmetric α-stable process (Xt)t≥0 with α ∈(0, 2) and V(x)=log?λ(1+|x|) with some λ>0, (TtV)t0 is intrinsically ultracontractive (or intrinsically supercontractive) if and only if λ>1, and (TtV)t0 is intrinsically hypercontractive if and only if λ1. Besides, we also investigate intrinsic contractivity properties of (TtV)t0 for the case that lim inf?|x|+V(x)<+

  • RESEARCH ARTICLE
    Zhenlong CHEN,Dongsheng WU,Yimin XIAO

    This paper is concerned with the smoothness (in the sense of Meyer- Watanabe) of the local times of Gaussian random fields. Sufficient and necessary conditions for the existence and smoothness of the local times, collision local times, and self-intersection local times are established for a large class of Gaussian random fields, including fractional Brownian motions, fractional Brownian sheets and solutions of stochastic heat equations driven by space-time Gaussian noise.

  • RESEARCH ARTICLE
    Zhen-Qing CHEN,Yan-Xia REN,Renming SONG,Rui ZHANG

    Consider a supercritical superprocess X = {Xt, t≥0} on a locally compact separable metric space (E,m). Suppose that the spatial motion of X is a Hunt process satisfying certain conditions and that the branching mechanism is of the form

    ψ(x,λ)=-a(x)λ+b(x)λ2+(0,+)(e-λy-1+λy)n(x,dy),?xE,λ>0,

    where aBb(E),bBb+(E), and n is a kernel from E to (0,+) satisfying sup?xE0+y2n(x,dy)<+. Put Ttf(x)=Pδx?f,Xt?. Suppose that the semigroup {Tt; t≥0}is compact. Let λ0 be the eigenvalue of the (possibly non-symmetric) generator L of {Tt}that has the largest real part among all the eigenvalues of L, which is known to be real-valued. Let ?0 and ?^0 be the eigenfunctions of L and L^(the dual of L) associated with λ0, respectively. Assume λ0>0. Under some conditions on the spatial motion and the ?0-transform of the semigroup {Tt}, we prove that for a large class of suitable functions f,

    lim?t+e-λ0t?f,Xt?=WE?^0(y)f(y)m(dy),?Pμ-a.s.,

    for any finite initial measure μ on E with compact support, where W is the martingale limit defined by W:=lim?t+e-λ0t??0,Xt?. Moreover, the exceptional set in the above limit does not depend on the initial measure μ and the function f.

  • RESEARCH ARTICLE
    Yunshyong CHOW

    This paper studies the long run behavior in evolutionary prisoner’s dilemma games. All players are assumed to sit around a circle and to interact only with their neighbors. It is known that full-defection is the unique long run equilibrium as the probability of players’ experimentation (or mutation) tends to zero in the best response dynamics. Here, it is shown that full-cooperation could emerge in the long run if one also cares for his neighbors in the bestresponse dynamics.

  • RESEARCH ARTICLE
    Fuqing GAO

    We consider laws of iterated logarithm for one-dimensional transient random walks in random environments. A quenched law of iterated logarithm is presented for transient random walks in general ergodic random environments, including independent identically distributed environments and uniformly ergodic environments.

  • RESEARCH ARTICLE
    Hui HE,Zenghu LI,Xiaowen ZHOU

    We investigate the branching structure coded by the excursion above zero of a spectrally positive Lévy process. The main idea is to identify the level of the Lévy excursion as the time and count the number of jumps upcrossing the level. By regarding the size of a jump as the birth site of a particle, we construct a branching particle system in which the particles undergo nonlocal branchings and deterministic spatial motions to the left on the positive half line. A particle is removed from the system as soon as it reaches the origin. Then a measure-valued Borel right Markov process can be defined as the counting measures of the particle system. Its total mass evolves according to a Crump- Mode-Jagers (CMJ) branching process and its support represents the residual life times of those existing particles. A similar result for spectrally negative Lévy process is established by a time reversal approach. Properties of the measurevalued processes can be studied via the excursions for the corresponding Lévy processes.

  • RESEARCH ARTICLE
    Huijie JI,Jinghai SHAO

    This work is devoted to calculating the first passage probabilities of one-dimensional diffusion processes. For a one-dimensional diffusion process, we construct a sequence of Markov chains so that their absorption probabilities approximate the first passage probability of the given diffusion process. This method is especially useful when dealing with time-dependent boundaries.

  • RESEARCH ARTICLE
    Junping LI,Xiangxiang HUANG,Juan WANG,Lina ZHANG

    We consider a multiclass service system with refusal and bulk-arrival. The properties regarding recurrence, ergodicity, and decay properties of such model are discussed. The explicit criteria regarding recurrence and ergodicity are obtained. The stationary distribution is given in the ergodic case. Then, the exact value of the decay parameter, denoted by λE, is obtained in the transient case. The criteria for the λE-recurrence are also obtained. Finally, the corresponding λE-invariant vector/measure is considered.

  • RESEARCH ARTICLE
    Yuanyuan LIU,Yuhui ZHANG

    We obtain sufficient criteria for central limit theorems (CLTs) for ergodic continuous-time Markov chains (CTMCs). We apply the results to establish CLTs for continuous-time single birth processes. Moreover, we present an explicit expression of the time average variance constant for a single birth process whenever a CLT exists. Several examples are given to illustrate these results.

  • RESEARCH ARTICLE
    Xiaocui MA,Fubao XI

    We consider the asymptotic property of the diffusion processes with Markovian switching. For a general case, we prove a large deviation principle for empirical measures of switching diffusion processes with small parameters.

  • RESEARCH ARTICLE
    Yutao MA,Yingzhe WANG

    We consider the diffusion process Xt on ?n with radial diffusion and drift coefficients. We prove that once the one-dimensional diffusion |Xt| has algebraic L2-convergence, so does Xt. And some classical examples are discussed.

  • RESEARCH ARTICLE
    Guangjun SHEN,Xiuwei YIN,Dongjin ZHU

    We study the problem of the approximation in law of the Rosenblatt sheet. We prove the convergence in law of two families of process to the Rosenblatt sheet: the first one is constructed from a Poisson process in the plane and the second one is based on random walks.

  • RESEARCH ARTICLE
    Xiao WU,Xiaolong ZOU,Xianping GUO

    This paper focuses on the constrained optimality problem (COP) of first passage discrete-time Markov decision processes (DTMDPs) in denumerable state and compact Borel action spaces with multi-constraints, state-dependent discount factors, and possibly unbounded costs. By means of the properties of a so-called occupation measure of a policy, we show that the constrained optimality problem is equivalent to an (infinite-dimensional) linear programming on the set of occupation measures with some constraints, and thus prove the existence of an optimal policy under suitable conditions. Furthermore, using the equivalence between the constrained optimality problem and the linear programming, we obtain an exact form of an optimal policy for the case of finite states and actions. Finally, as an example, a controlled queueing system is given to illustrate our results.