Polynomial Tail Decay for Stationary Measures
Samuel Kittle, Constantin Kogler
TL;DR
The paper analyzes polynomial tail decay for stationary measures arising from contracting-on-average random walks on complete metric spaces. It proves existence and uniqueness of a stationary measure $\nu$ for finitely supported $\mu$ with contraction rate $\chi_{\mu}<0$ and establishes a polynomial tail bound $\nu(\{d(x,y) \ge R\}) \ll R^{-\alpha}$, with a Lyapunov-exponent variant $\lambda_{\mu}<0$ under a large-deviation hypothesis. The approach relies on constructing $\nu$ as a limit of random products and applying a large-deviation principle, avoiding renewal theory and extending to non-finitely supported $\mu$ via the compact-open topology. The work also discusses consequences for self-similar and self-affine measures, including a polynomial lower bound in the self-similar setting and finite differential entropy for polynomial-tail stationary measures, connecting to broader results in the literature.
Abstract
We show on complete metric spaces a polynomial tail decay for stationary measures of contracting on average generating measures.
