Posterior Convergence Analysis of $α$-Stable Sheets

Abstract

This paper is concerned with the theoretical understanding of $α$-stable sheets $U$ on $\mathbb{R}^d$. Our motivation for this is in the context of Bayesian inverse problems, where we consider these processes as prior distributions, aiming to quantify information of the posterior. We derive convergence results referring to finite-dimensional approximations of infinite-dimensional random variables. In doing so we use a number of variants which these sheets can take, such as a stochastic integral representation, but also random series expansions through Poisson processes. Our proofs will rely on the fact of whether $U$ can omit $L^p$-sample paths. To aid with the convergence of the finite approximations we provide a natural discretization to represent the prior. Aside from convergence of these stable sheets we address whether both well-posedness and well-definiteness of the inverse problem can be attained.