Classifying spaces for families of abelian subgroups of braid groups, RAAGs and graphs of abelian groups

Fuente: arXiv
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Main Author: Álvarez, Porfirio L. León
Format: Preprint
Published: 2023
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author Álvarez, Porfirio L. León
author_facet Álvarez, Porfirio L. León
contents Given a group $G$ and an integer $n\geq 0$ we consider the family $\mathcal{F}_n$ of all virtually abelian subgroups of $G$ of rank at most $n$. In this article we prove that for each $n\ge2$ the Bredon cohomology, with respect to the family $\mathcal{F}_n$, of a free abelian group with rank $k > n$ is nontrivial in dimension $k+n$; this answers a question of Corob Cook, Moreno, Nucinkis and Pasini. As an application, we compute the minimal dimension of a classifying space for the family $\mathcal{F}_n$ for braid groups, right-angled Artin groups, and graphs of groups whose vertex groups are infinite finitely generated virtually abelian groups, for all $n\ge2$. The main tools that we use are the Mayer-Vietoris sequence for Bredon cohomology, Bass-Serre theory, and the Lück-Weiermann construction.
format Preprint
id arxiv_https___arxiv_org_abs_2304_14315
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Classifying spaces for families of abelian subgroups of braid groups, RAAGs and graphs of abelian groups
Álvarez, Porfirio L. León
Group Theory
Algebraic Topology
Given a group $G$ and an integer $n\geq 0$ we consider the family $\mathcal{F}_n$ of all virtually abelian subgroups of $G$ of rank at most $n$. In this article we prove that for each $n\ge2$ the Bredon cohomology, with respect to the family $\mathcal{F}_n$, of a free abelian group with rank $k > n$ is nontrivial in dimension $k+n$; this answers a question of Corob Cook, Moreno, Nucinkis and Pasini. As an application, we compute the minimal dimension of a classifying space for the family $\mathcal{F}_n$ for braid groups, right-angled Artin groups, and graphs of groups whose vertex groups are infinite finitely generated virtually abelian groups, for all $n\ge2$. The main tools that we use are the Mayer-Vietoris sequence for Bredon cohomology, Bass-Serre theory, and the Lück-Weiermann construction.
title Classifying spaces for families of abelian subgroups of braid groups, RAAGs and graphs of abelian groups
topic Group Theory
Algebraic Topology
url https://arxiv.org/abs/2304.14315