Right-angled Artin groups and the cohomology basis graph

Fuente: arXiv
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Main Authors: Flores, Ramón, Kahrobaei, Delaram, Koberda, Thomas, Coz, Corentin Le
Format: Preprint
Published: 2023
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author Flores, Ramón
Kahrobaei, Delaram
Koberda, Thomas
Coz, Corentin Le
author_facet Flores, Ramón
Kahrobaei, Delaram
Koberda, Thomas
Coz, Corentin Le
contents Let $Γ$ be a finite graph and let $A(Γ)$ be the corresponding right-angled Artin group. From an arbitrary basis $\mathcal B$ of $H^1(A(Γ),\mathbb F)$ over an arbitrary field, we construct a natural graph $Γ_{\mathcal B}$ from the cup product, called the \emph{cohomology basis graph}. We show that $Γ_{\mathcal B}$ always contains $Γ$ as a subgraph. This provides an effective way to reconstruct the defining graph $Γ$ from the cohomology of $A(Γ)$, to characterize the planarity of the defining graph from the algebra of $A(Γ)$, and to recover many other natural graph-theoretic invariants. We also investigate the behavior of the cohomology basis graph under passage to elementary subminors, and show that it is not well-behaved under edge contraction.
format Preprint
id arxiv_https___arxiv_org_abs_2309_05495
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Right-angled Artin groups and the cohomology basis graph
Flores, Ramón
Kahrobaei, Delaram
Koberda, Thomas
Coz, Corentin Le
Group Theory
Combinatorics
Geometric Topology
Let $Γ$ be a finite graph and let $A(Γ)$ be the corresponding right-angled Artin group. From an arbitrary basis $\mathcal B$ of $H^1(A(Γ),\mathbb F)$ over an arbitrary field, we construct a natural graph $Γ_{\mathcal B}$ from the cup product, called the \emph{cohomology basis graph}. We show that $Γ_{\mathcal B}$ always contains $Γ$ as a subgraph. This provides an effective way to reconstruct the defining graph $Γ$ from the cohomology of $A(Γ)$, to characterize the planarity of the defining graph from the algebra of $A(Γ)$, and to recover many other natural graph-theoretic invariants. We also investigate the behavior of the cohomology basis graph under passage to elementary subminors, and show that it is not well-behaved under edge contraction.
title Right-angled Artin groups and the cohomology basis graph
topic Group Theory
Combinatorics
Geometric Topology
url https://arxiv.org/abs/2309.05495