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Bibliographic Details
Main Author: Grilliette, Will
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2403.13165
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author Grilliette, Will
author_facet Grilliette, Will
contents By applying simplification operations to categories of multigraphs, several natural graph operations are shown to demonstrate categorical issues. The replacement of an undirected edge with a directed cycle for digraphs admits both a left and a right adjoint, while the analogous operation for quivers only admits a left adjoint. The clique-replacement graph, intersection graph, and dual hypergraph fail to be functorial with traditional graph homomorphisms. The three failures are remedied by considering weak set-system homomorphisms, which form a category isomorphic to both the category of incidence structures and a lax comma category.
format Preprint
id arxiv_https___arxiv_org_abs_2403_13165
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Simplification & Incidence: How an Incidence-focused Perspective Patches Category-theoretic Problems in Graph Theory
Grilliette, Will
Category Theory
Combinatorics
05C20, 05C65, 18A25, 18A40
By applying simplification operations to categories of multigraphs, several natural graph operations are shown to demonstrate categorical issues. The replacement of an undirected edge with a directed cycle for digraphs admits both a left and a right adjoint, while the analogous operation for quivers only admits a left adjoint. The clique-replacement graph, intersection graph, and dual hypergraph fail to be functorial with traditional graph homomorphisms. The three failures are remedied by considering weak set-system homomorphisms, which form a category isomorphic to both the category of incidence structures and a lax comma category.
title Simplification & Incidence: How an Incidence-focused Perspective Patches Category-theoretic Problems in Graph Theory
topic Category Theory
Combinatorics
05C20, 05C65, 18A25, 18A40
url https://arxiv.org/abs/2403.13165