Finite presentability of twisted Brin-Thompson groups
Abstract
Given a group acting faithfully on a set , we characterize precisely when the twisted Brin-Thompson group is finitely presented. The answer is that is finitely presented if and only if we have the following: is finitely presented, the action of on has finitely many orbits of two-element subsets of , and the stabilizer in of any element of is finitely generated. Since twisted Brin-Thompson groups are simple, a consequence is that any subgroup of a group admitting an action as above satisfies the Boone-Higman conjecture. In the course of proving this, we also establish a sufficient condition for a group acting cocompactly on a simply connected complex to be finitely presented, even if certain edge stabilizers are not finitely generated, which may be of independent interest.
Keywords
Cite
@article{arxiv.2405.18354,
title = {Finite presentability of twisted Brin-Thompson groups},
author = {Matthew C. B. Zaremsky},
journal= {arXiv preprint arXiv:2405.18354},
year = {2024}
}
Comments
20 pages. V2: Accepted version, to appear in Proc. Roy. Soc. Edinburgh Sect. A