English

Gromov boundaries as Markov compacta

Geometric Topology 2015-03-17 v1

Abstract

We prove that the Gromov boundary of every hyperbolic group is homeomorphic to some Markov compactum. Our reasoning is based on constructing a sequence of covers of G\partial G, which is quasi-GG-invariant wrt. the ball NN-type (defined by Cannon) for NN sufficiently large. We also ensure certain additional properties for the inverse system representing G\partial G, leading to a finite description which defines it uniquely. By defining a natural metric on the inverse limit limKn\lim K_n and proving it to be bi-Lipschitz equivalent to an accordingly chosen visual metric on G\partial G, we prove that our construction enables providing a simplicial description of the natural quasi-conformal structure on G\partial G. We also point out that the initial system of covers can be modified so that all the simplexes in the resulting inverse system are of dimension less than or equal to dimG\dim \partial G. We also generalize --- from the torsion-free case to all finitely generated hyperbolic groups --- a theorem guaranteeing the existence of a finite representation of G\partial G of another kind, namely a semi-Markovian structure (which can be understood as an analogue of the well-known automatic structure of GG itself).

Keywords

Cite

@article{arxiv.1503.04577,
  title  = {Gromov boundaries as Markov compacta},
  author = {Dominika Pawlik},
  journal= {arXiv preprint arXiv:1503.04577},
  year   = {2015}
}
R2 v1 2026-06-22T08:53:49.542Z