Clique covers of H-free graphs

It takes <i>n</i><sup>2</sup>/4 cliques to cover all the edges of a complete bipartite graph <i>K</i><sub><i>n/2,n/2</i></sub>, but how many cliques does it take to cover all the edges of a graph <i>G</i> if <i>G</i>...

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Main Authors: Nguyen, T, Scott, A, Seymour, P, Thomassé, S
Format: Journal article
Language:English
Published: Elsevier 2023
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author Nguyen, T
Scott, A
Seymour, P
Thomassé, S
author_facet Nguyen, T
Scott, A
Seymour, P
Thomassé, S
author_sort Nguyen, T
collection OXFORD
description It takes <i>n</i><sup>2</sup>/4 cliques to cover all the edges of a complete bipartite graph <i>K</i><sub><i>n/2,n/2</i></sub>, but how many cliques does it take to cover all the edges of a graph <i>G</i> if <i>G</i> has no <i>K</i><sub><i>t,t</i></sub> induced subgraph? We prove that <i>O</i>(<i>n</i><sup><i>2—1/(2t)</i></sup>) cliques suffice for every <i>n</i>-vertex graph; and also prove that, even for graphs with no stable set of size four, we may need more than linearly many cliques. This settles two questions discussed at a recent conference in Lyon.
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spelling oxford-uuid:2446685d-4341-4d57-91d7-a8d7c376455e2024-04-29T10:07:24ZClique covers of H-free graphsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2446685d-4341-4d57-91d7-a8d7c376455eEnglishSymplectic ElementsElsevier2023Nguyen, TScott, ASeymour, PThomassé, SIt takes <i>n</i><sup>2</sup>/4 cliques to cover all the edges of a complete bipartite graph <i>K</i><sub><i>n/2,n/2</i></sub>, but how many cliques does it take to cover all the edges of a graph <i>G</i> if <i>G</i> has no <i>K</i><sub><i>t,t</i></sub> induced subgraph? We prove that <i>O</i>(<i>n</i><sup><i>2—1/(2t)</i></sup>) cliques suffice for every <i>n</i>-vertex graph; and also prove that, even for graphs with no stable set of size four, we may need more than linearly many cliques. This settles two questions discussed at a recent conference in Lyon.
spellingShingle Nguyen, T
Scott, A
Seymour, P
Thomassé, S
Clique covers of H-free graphs
title Clique covers of H-free graphs
title_full Clique covers of H-free graphs
title_fullStr Clique covers of H-free graphs
title_full_unstemmed Clique covers of H-free graphs
title_short Clique covers of H-free graphs
title_sort clique covers of h free graphs
work_keys_str_mv AT nguyent cliquecoversofhfreegraphs
AT scotta cliquecoversofhfreegraphs
AT seymourp cliquecoversofhfreegraphs
AT thomasses cliquecoversofhfreegraphs