Commensurability of lattices in right-angled buildings

Fuente: arXiv
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Autore principale: Shepherd, Sam
Natura: Preprint
Pubblicazione: 2022
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author Shepherd, Sam
author_facet Shepherd, Sam
contents Let $Γ$ be a graph product of finite groups, with finite underlying graph, and let $Δ$ be the associated right-angled building. We prove that a uniform lattice $Λ$ in the cubical automorphism group Aut$(Δ)$ is weakly commensurable to $Γ$ if and only if all convex subgroups of $Λ$ are separable. As a corollary, any two finite special cube complexes with universal cover $Δ$ have a common finite cover. An important special case of our theorem is where $Γ$ is a right-angled Coxeter group and $Δ$ is the associated Davis complex. We also obtain an analogous result for right-angled Artin groups. In addition, we deduce quasi-isometric rigidity for the group $Γ$ when $Δ$ has the structure of a Fuchsian building.
format Preprint
id arxiv_https___arxiv_org_abs_2203_01210
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Commensurability of lattices in right-angled buildings
Shepherd, Sam
Group Theory
20F65 (Primary) 20F55, 57M10 (Secondary)
Let $Γ$ be a graph product of finite groups, with finite underlying graph, and let $Δ$ be the associated right-angled building. We prove that a uniform lattice $Λ$ in the cubical automorphism group Aut$(Δ)$ is weakly commensurable to $Γ$ if and only if all convex subgroups of $Λ$ are separable. As a corollary, any two finite special cube complexes with universal cover $Δ$ have a common finite cover. An important special case of our theorem is where $Γ$ is a right-angled Coxeter group and $Δ$ is the associated Davis complex. We also obtain an analogous result for right-angled Artin groups. In addition, we deduce quasi-isometric rigidity for the group $Γ$ when $Δ$ has the structure of a Fuchsian building.
title Commensurability of lattices in right-angled buildings
topic Group Theory
20F65 (Primary) 20F55, 57M10 (Secondary)
url https://arxiv.org/abs/2203.01210