English

Hyperfiniteness of boundary actions of acylindrically hyperbolic groups

Group Theory 2024-09-17 v2 Logic

Abstract

We prove that for any countable acylidrically hyperbolic group GG, there exists a generating set SS of GG such that the corresponding Cayley graph Γ(G,S)\Gamma(G,S) is hyperbolic, Γ(G,X)>2|\partial\Gamma(G,X)|>2, the natural action of GG on Γ(G,S)\Gamma(G,S) is acylindrical, and the natural action of GG on the Gromov boundary Γ(G,S)\partial\Gamma(G,S) is hyperfinite. This result broadens a class of groups that admit a non-elementary acylindrical action on a hyperbolic space with hyperfinite boundary action.

Keywords

Cite

@article{arxiv.2307.09790,
  title  = {Hyperfiniteness of boundary actions of acylindrically hyperbolic groups},
  author = {Koichi Oyakawa},
  journal= {arXiv preprint arXiv:2307.09790},
  year   = {2024}
}

Comments

Section 5 "Application to topologically amenable actions" was added. Appeared in Forum of Mathematics, Sigma