A general Choquet–Deny theorem for nilpotent groups
For a regular, compact, polynomially convex circled set in , we construct a sequence of pairs of homogeneous polynomials in two variables with
Dans le cadre de l’axiomatique de M. Brelot, et en utilisant la théorie des fonctions harmoniques adjointes de Madame R.M. Hervé, on caractérise la propriété de quasi-analycité notée : toute fonction harmonique adjointe dans un domaine est nulle dès qu’elle est nulle au voisinage d’un point. On montre que est équivalente à une propriété d’approximation de toute fonction réelle finie continue sur les frontières d’ouverts relativement compacts. Cette approximation est réalisée à l’aide de différences...
We investigate properties of harmonic functions of the symmetric stable Lévy process on without the assumption that the process is rotation invariant. Our main goal is to prove the boundary Harnack principle for Lipschitz domains. To this end we improve the estimates for the Poisson kernel obtained in a previous work. We also investigate properties of harmonic functions of Feynman-Kac semigroups based on the stable process. In particular, we prove the continuity and the Harnack inequality for...
We show the equivalence of some different definitions of p-superharmonic functions given in the literature. We also provide several other characterizations of p-superharmonicity. This is done in complete metric spaces equipped with a doubling measure and supporting a Poincaré inequality. There are many examples of such spaces. A new one given here is the union of a line (with the one-dimensional Lebesgue measure) and a triangle (with a two-dimensional weighted Lebesgue measure). Our results also...