English

Actions of small cancellation groups on hyperbolic spaces

Group Theory 2018-07-31 v2

Abstract

We generalize Gruber--Sisto's construction of the coned--off graph of a small cancellation group to build a partially ordered set TC\mathcal{TC} of cobounded actions of a given small cancellation group whose smallest element is the action on the Gruber--Sisto coned--off graph. In almost all cases TC\mathcal{TC} is incredibly rich: it has a largest element if and only if it has exactly 1 element, and given any two distinct comparable actions [GX][GY][G\curvearrowright X] \preceq [G\curvearrowright Y] in this poset, there is an embeddeding ι:P(ω)TC\iota:P(\omega)\to\mathcal{TC} such that ι()=[GX]\iota(\emptyset)=[G\curvearrowright X] and ι(N)=[GY]\iota(\mathbb N)=[G\curvearrowright Y]. We use this poset to prove that there are uncountably many quasi--isometry classes of finitely generated group which admit two cobounded acylindrical actions on hyperbolic spaces such that there is no action on a hyperbolic space which is larger than both.

Keywords

Cite

@article{arxiv.1807.10524,
  title  = {Actions of small cancellation groups on hyperbolic spaces},
  author = {Carolyn Abbott and David Hume},
  journal= {arXiv preprint arXiv:1807.10524},
  year   = {2018}
}

Comments

42 pages, 14 figures

R2 v1 2026-06-23T03:16:44.490Z