Marches de Harris sur les groupes localement compacts. II
We develop a potential theoretic approach to the problem of metastability for reversible diffusion processes with generators of the form on or subsets of , where is a smooth function with finitely many local minima. In analogy to previous work on discrete Markov chains, we show that metastable exit times from the attractive domains of the minima of can be related, up to multiplicative errors that tend to one as , to the capacities of suitably constructed sets. We show that these capacities...
We continue the analysis of the problem of metastability for reversible diffusion processes, initiated in [BEGK3], with a precise analysis of the low-lying spectrum of the generator. Recall that we are considering processes with generators of the form on or subsets of , where is a smooth function with finitely many local minima. Here we consider only the generic situation where the depths of all local minima are different. We show that in general the exponentially small part of the spectrum...
We study minimal thinness in the half-space for a large class of subordinate Brownian motions. We show that the same test for the minimal thinness of a subset of below the graph of a nonnegative Lipschitz function is valid for all processes in the considered class. In the classical case of Brownian motion this test was proved by Burdzy.
est un processus de Markov sur un espace localement compact, et est une fonction excessive. Soit une famille de temps d’arrêt est -harmonique si pour tout , pour tout temps d’arrêt appartenant à . est un potentiel si sa plus grande minorante forte -harmonique est nulle. La plus grande minorante forte -harmonique de est égale à la somme de deux fonctions excessives qui sont étudiées. On déduit différentes caractérisations des -potentiels suivant les propriétés de la famille...