Le semi-groupe d'une diffusion en liaison avec les trajectoires
La topologie fine a été introduite pour fournir un cadre intrinsèque à la théorie du potentiel. Cependant les ouverts fins ne possèdent pas certaines propriétés dont celle de Lindeberg. Cette considération nous conduit à introduire des topologies moins finies appelées -topologies ). Nous démontrons pour ces -topologies un critère analogue à celui établi par N. Wiener, pour les ouverts fins. Puis nous nous intéressons à la théorie des équations différentielles stochastiques sur les -ouverts.
We prove admissible convergence to the boundary of functions that are harmonic on a subset of a non-homogeneous tree equipped with a transition operator that satisfies uniform bounds suitable for transience. The approach is based on a discrete Green formula, suitable estimates for the Green and Poisson kernel and an analogue of the Lusin area function.
In Landkof’s monograph [8, p. 213] it is asserted that logarithmic capacity is strongly subadditive, and therefore that it is a Choquet capacity. An example demonstrating that logarithmic capacity is not even subadditive can be found e.gi̇n [6, Example 7.20], see also [3, p. 803]. In this paper we will show this fact with the help of the fine topology in potential theory.
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...