Gromov boundaries as Markov compacta
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 , which is quasi--invariant wrt. the ball -type (defined by Cannon) for sufficiently large. We also ensure certain additional properties for the inverse system representing , leading to a finite description which defines it uniquely. By defining a natural metric on the inverse limit and proving it to be bi-Lipschitz equivalent to an accordingly chosen visual metric on , we prove that our construction enables providing a simplicial description of the natural quasi-conformal structure on . 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 . We also generalize --- from the torsion-free case to all finitely generated hyperbolic groups --- a theorem guaranteeing the existence of a finite representation of of another kind, namely a semi-Markovian structure (which can be understood as an analogue of the well-known automatic structure of itself).
Cite
@article{arxiv.1503.04577,
title = {Gromov boundaries as Markov compacta},
author = {Dominika Pawlik},
journal= {arXiv preprint arXiv:1503.04577},
year = {2015}
}