English

Similar relatively hyperbolic actions of a group

Group Theory 2014-03-21 v3

Abstract

Let a discrete group GG possess two convergence actions by homeomorphisms on compacta XX and YY. Consider the following question: does there exist a convergence action GZG{\curvearrowright}Z on a compactum ZZ and continuous equivariant maps XZYX\leftarrow Z\to Y? We call the space ZZ (and action of GG on it) {\it pullback} space (action). In such general setting a negative answer follows from a recent result of O. Baker and T. Riley [BR]. Suppose, in addition, that the initial actions are relatively hyperbolic that is they are non-parabolic and the induced action on the distinct pairs are cocompact. Then the existence of the pullback space if GG is finitely generated follows from \cite{Ge2}. The main result of the paper claims that the pullback space exists if and only if the maximal parabolic subgroups of one of the actions are dynamically quasiconvex for the other one. We provide an example of two relatively hyperbolic actions of the free group GG of countable rank for which the pullback action does not exist. We study an analog of the notion of geodesic flow for relatively hyperbolic groups. Further these results are used to prove the main theorem.

Keywords

Cite

@article{arxiv.1305.6649,
  title  = {Similar relatively hyperbolic actions of a group},
  author = {Victor Gerasimov and Leonid Potyagailo},
  journal= {arXiv preprint arXiv:1305.6649},
  year   = {2014}
}