English

Spatial models for boolean actions in the infinite measure-preserving setup

Dynamical Systems 2025-04-08 v2 Group Theory Operator Algebras

Abstract

We show that up to a null set, every infinite measure-preserving action of a locally compact Polish group can be turned into a continuous measure-preserving action on a locally compact Polish space where the underlying measure is Radon. We also investigate the distinction between spatial and boolean actions in the infinite measure-preserving setup. In particular, we extend Kwiatkowska and Solecki's Point Realization Theorem to the infinite measure setup. We finally obtain a streamlined proof of a recent result of Avraham-Re'em and Roy: L\'evy groups cannot admit nontrivial continuous measure-preserving actions on Polish spaces when the measure is locally finite.

Keywords

Cite

@article{arxiv.2406.02401,
  title  = {Spatial models for boolean actions in the infinite measure-preserving setup},
  author = {Fabien Hoareau and François Le Maître},
  journal= {arXiv preprint arXiv:2406.02401},
  year   = {2025}
}

Comments

Numerous fixes following referee comments; Spatial Realization result extended to isometry groups of locally compact separable metric spaces. Comments welcome!

R2 v1 2026-06-28T16:53:05.772Z