arXiv subjects

Y. Kondratiev

Publications and source records attributed to Y. Kondratiev.

4 recordsLinked to original sources

arXiv2021

Random Time Dynamical Systems

In this paper, we introduce the concept of random time changes in dynamical systems. The sub- ordination principle may be applied to study the long time behavior of the random time systems. We show, under certain assumptions on the class of random time, that the subordinated system exhibits a slower time decay which is determined by the random time characteristics. Along the path asymp- totic, a random time change is reflected in the new velocity of the resulting dynamics.

math.DS↗

arXiv2014

Laplace operators in gamma analysis

Let $\mathbb K(\mathbb R^d)$ denote the cone of discrete Radon measures on $\mathbb R^d$. The gamma measure $\mathcal G$ is the probability measure on $\mathbb K(\mathbb R^d)$ which is a measure-valued Lévy process with intensity measure $s^{-1}e^{-s}\,ds$ on $(0,\infty)$. We study a class of Laplace-type operators in $L^2(\mathbb K(\mathbb R^d),\mathcal G)$. These operators are defined as generators of certain (local) Dirichlet forms. The main result of the papers is the essential self-adjointness of these operators on a set of `test' cylinder functions on $\mathbb K(\mathbb R^d)$.

math.PR↗

arXiv2007

Non-equilibrium stochastic dynamics in continuum: The free case

We study the problem of identification of a proper state-space for the stochastic dynamics of free particles in continuum, with their possible birth and death. In this dynamics, the motion of each separate particle is described by a fixed Markov process $M$ on a Riemannian manifold $X$. The main problem arising here is a possible collapse of the system, in the sense that, though the initial configuration of particles is locally finite, there could exist a compact set in $X$ such that, with probability one, infinitely many particles will arrive at this set at some time $t>0$. We assume that $X$ has infinite volume and, for each $α\ge1$, we consider the set $Θ_α$ of all infinite configurations in $X$ for which the number of particles in a compact set is bounded by a constant times the $α$-th power of the volume of the set. We find quite general conditions on the process $M$ which guarantee that the corresponding infinite particle process can start at each configuration from $Θ_α$, will never leave $Θ_α$, and has cadlag (or, even, continuous) sample paths in the vague topology. We consider the following examples of applications of our results: Brownian motion on the configuration space, free Glauber dynamics on the configuration space (or a birth-and-death process in $X$), and free Kawasaki dynamics on the configuration space. We also show that if $X=\mathbb R^d$, then for a wide class of starting distributions, the (non-equilibrium) free Glauber dynamics is a scaling limit of (non-equilibrium) free Kawasaki dynamics.

math.PR↗

arXiv2001

Laplace operators in deRham complexes associated with measures on configuration spaces

Let $Γ_X$ denote the space of all locally finite configurations in a complete, stochastically complete, connected, oriented Riemannian manifold $X$, whose volume measure $m$ is infinite. In this paper, we construct and study spaces $L^2_μΩ^n$ of differential $n$-forms over $Γ_X$ that are square integrable with respect to a probability measure $μ$ on $Γ_X$. The measure $μ$ is supposed to satisfy the condition $Σ_m'$ (generalized Mecke identity) well known in the theory of point processes. On $L^2_μΩ^n$, we introduce bilinear forms of Bochner and deRham type. We prove their closabilty and call the generators of the corresponding closures the Bochner and deRham Laplacian, respectively. We prove that both operators contain in their domain the set of all smooth local forms. We show that, under a rather general assumption on the measure $μ$, the space of all Bochner-harmonic $μ$-square integrable forms on $Γ_X$ consists only of the zero form. Finally, a Weitzenböck type formula connecting the Bochner and deRham Laplacians is obtained. As examples, we consider (mixed) Poisson measures, Ruelle type measures on $Γ_{{\Bbb R}^d}$, and Gibbs measures in the low activity--high temperature regime, as well as Gibbs measures with a positive interaction potential on $Γ_X$.

math.PR↗