Homotopy Covers of Graphs

Fuente: arXiv
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Main Authors: Chih, Tien, Scull, Laura
Format: Preprint
Published: 2020
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_version_ 1866914391509696512
author Chih, Tien
Scull, Laura
author_facet Chih, Tien
Scull, Laura
contents We develop a theory of $\times$-homotopy, fundamental groupoids and covering spaces that apply to non-simple graphs, generalizing existing results for simple graphs. We prove that $\times$-homotopies from finite graphs can be decomposed into moves which adjust at most one vertex at a time, generalizing the spider lemma of \cite{CS1}. We define a notion of homotopy covering map and develop a theory of universal covers and deck transformations, generalizing \cites{TardifWroncha, Matsushita} to non-simple graphs. We examine the case of reflexive graphs, where each vertex has at least one loop. We also prove that these homotopy covering maps satisfy a homotopy lifting property for arbitrary graph homomorphisms, generalizing path lifting results of \cites{Matsushita, TardifWroncha}.
format Preprint
id arxiv_https___arxiv_org_abs_2012_05378
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Homotopy Covers of Graphs
Chih, Tien
Scull, Laura
Combinatorics
05C25, 05E18, 05C38, 20L05, 05C30, 05C60
We develop a theory of $\times$-homotopy, fundamental groupoids and covering spaces that apply to non-simple graphs, generalizing existing results for simple graphs. We prove that $\times$-homotopies from finite graphs can be decomposed into moves which adjust at most one vertex at a time, generalizing the spider lemma of \cite{CS1}. We define a notion of homotopy covering map and develop a theory of universal covers and deck transformations, generalizing \cites{TardifWroncha, Matsushita} to non-simple graphs. We examine the case of reflexive graphs, where each vertex has at least one loop. We also prove that these homotopy covering maps satisfy a homotopy lifting property for arbitrary graph homomorphisms, generalizing path lifting results of \cites{Matsushita, TardifWroncha}.
title Homotopy Covers of Graphs
topic Combinatorics
05C25, 05E18, 05C38, 20L05, 05C30, 05C60
url https://arxiv.org/abs/2012.05378