English

Invariant random subgroups of groups acting on hyperbolic spaces

Group Theory 2022-11-21 v4 Dynamical Systems

Abstract

Suppose that a group GG acts non-elementarily on a hyperbolic space SS and does not fix any point of S\partial S. A subgroup HGH\le G is said to be geometrically dense in GG if the limit sets of HH and GG coincide and HH does not fix any point of S\partial S. We prove that every invariant random subgroup of GG is either geometrically dense or contained in the elliptic radical (i.e., the maximal normal elliptic subgroup of GG). In particular, every ergodic measure preserving action of an acylindrically hyperbolic group on a Borel probability space (X,μ)(X,\mu) either has finite stabilizers μ\mu-almost surely or otherwise the stabilizers are very large (in particular, acylindrically hyperbolic) μ\mu-almost surely.

Keywords

Cite

@article{arxiv.1510.07710,
  title  = {Invariant random subgroups of groups acting on hyperbolic spaces},
  author = {D. Osin},
  journal= {arXiv preprint arXiv:1510.07710},
  year   = {2022}
}

Comments

Some typos are corrected

R2 v1 2026-06-22T11:29:32.312Z