A remark on subharmonicity for symmetric Dirichlet forms
Kazuhiro Kuwae, Rong Lei, Ludovico Marini
TL;DR
The article extends stochastic characterizations of subharmonicity to general symmetric regular Dirichlet forms by removing the Local Boundedness assumption, enabling a unified treatment of $\mathscr{E}$-subharmonic functions for $\alpha\ge0$. It develops an energy-based definition, proves equivalence with stochastic subharmonicity notions, and shows invariance under time-change, culminating in a strong maximum principle under irreducibility. The results are illustrated through Brownian motion and relativistic $\alpha$-stable processes, highlighting applicability to non-diffusion settings and non-locally bounded functions. This broadens the potential-theoretic toolkit for Dirichlet forms and supports future analyses of irregular Markov processes.
Abstract
We remove the local boundedness for $\mathscr{E}_α$-subharmonicity in the framework of (not necessarily strongly local) regular symmetric Dirichlet form $(\mathscr{E},D(\mathscr{E}))$ with $α\geq0$ and establish the stochastic characterization for $\mathscr{E}$-subharmonic functions without assuming the local boundedness.
