BNSR-Invariants of Surface Houghton Groups

Fuente: arXiv
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Main Authors: Torgerson, Noah, West, Jeremy
Format: Preprint
Published: 2024
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_version_ 1866915636804845568
author Torgerson, Noah
West, Jeremy
author_facet Torgerson, Noah
West, Jeremy
contents The surface Houghton groups $\mathcal{H}_{n}$ are a family of groups generalizing Houghton groups $H_n$, which are constructed as asymptotically rigid mapping class groups. We give a complete computation of the BNSR-invariants $Σ^{m}(P\mathcal{H}_{n})$ of their intersection with the pure mapping class group. To do so, we prove that the associated Stein--Farley cube complex is CAT(0), and we adapt Zaremsky's method for computing the BNSR-invariants of the Houghton groups. As a consequence, we give a criterion for when subgroups of $H_n$ and $P\mathcal{H}_{n}$ having the same finiteness length as their parent group are finite index. We also discuss the failure of some of these groups to be co-Hopfian.
format Preprint
id arxiv_https___arxiv_org_abs_2403_04941
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle BNSR-Invariants of Surface Houghton Groups
Torgerson, Noah
West, Jeremy
Geometric Topology
Group Theory
20F65, 57K20, 57M07
The surface Houghton groups $\mathcal{H}_{n}$ are a family of groups generalizing Houghton groups $H_n$, which are constructed as asymptotically rigid mapping class groups. We give a complete computation of the BNSR-invariants $Σ^{m}(P\mathcal{H}_{n})$ of their intersection with the pure mapping class group. To do so, we prove that the associated Stein--Farley cube complex is CAT(0), and we adapt Zaremsky's method for computing the BNSR-invariants of the Houghton groups. As a consequence, we give a criterion for when subgroups of $H_n$ and $P\mathcal{H}_{n}$ having the same finiteness length as their parent group are finite index. We also discuss the failure of some of these groups to be co-Hopfian.
title BNSR-Invariants of Surface Houghton Groups
topic Geometric Topology
Group Theory
20F65, 57K20, 57M07
url https://arxiv.org/abs/2403.04941