Reversibility of elliptical slice sampling revisited
Mareike Hasenpflug, Viacheslav Telezhnikov, Daniel Rudolf
TL;DR
The paper addresses whether elliptical slice sampling (ESS) remains well-defined and stationary when the target distribution lives on an infinite-dimensional Hilbert space, with the posterior $\mu(d x)=Z^{-1}\rho(x)\mu_0(d x)$ and $\mu_0=\mathcal{N}(0,C)$. It develops a circle-angle shrinkage representation, proves termination under the mild condition that $\rho$ is lower semicontinuous, and establishes that the ESS transition kernel is reversible w.r.t. $\mu$ and that the induced operator on $L^2_\mu$ is positive semi-definite. The key technical tool is the stopped shrinkage kernel $Q_S$ on open-on-circle sets $S$, together with a representation of the ESS update as a mixture over angles; these yield a pathway to dimension-independent mixing and motivate spectral-gap analyses and extensions to approximate ESS and related slice-sampling variants. The results advance the theoretical understanding of slice sampling on function spaces and suggest practical directions for coupling constructions and broadened applicability.
Abstract
We extend elliptical slice sampling, a Markov chain transition kernel suggested in Murray, Adams and MacKay 2010, to infinite-dimensional separable Hilbert spaces and discuss its well-definedness. We point to a regularity requirement, provide an alternative proof of the desirable reversibility property and show that it induces a positive semi-definite Markov operator. Crucial within the proof of the formerly mentioned results is the analysis of a shrinkage Markov chain that may be interesting on its own.
