Induced subgraphs of graphs with large chromatic number. VI. Banana trees

We investigate which graphs H have the property that in every graph with bounded clique number and sufficiently large chromatic number, some induced subgraph is isomorphic to a subdivision of H. In an earlier paper, the first author proved that every tree has this property; and in another earlier pa...

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Príomhchruthaitheoirí: Scott, A, Seymour, P
Formáid: Journal article
Teanga:English
Foilsithe / Cruthaithe: Elsevier 2020
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author Scott, A
Seymour, P
author_facet Scott, A
Seymour, P
author_sort Scott, A
collection OXFORD
description We investigate which graphs H have the property that in every graph with bounded clique number and sufficiently large chromatic number, some induced subgraph is isomorphic to a subdivision of H. In an earlier paper, the first author proved that every tree has this property; and in another earlier paper with Maria Chudnovsky, we proved that every cycle has this property. Here we give a common generalization. Say a “banana” is the union of a set of paths all with the same ends but otherwise disjoint. We prove that if H is obtained from a tree by replacing each edge by a banana then H has the property mentioned.
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spelling oxford-uuid:22570a98-ff1c-41f3-8558-5e9bdc7565532022-03-26T11:38:16ZInduced subgraphs of graphs with large chromatic number. VI. Banana treesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:22570a98-ff1c-41f3-8558-5e9bdc756553EnglishSymplectic ElementsElsevier2020Scott, ASeymour, PWe investigate which graphs H have the property that in every graph with bounded clique number and sufficiently large chromatic number, some induced subgraph is isomorphic to a subdivision of H. In an earlier paper, the first author proved that every tree has this property; and in another earlier paper with Maria Chudnovsky, we proved that every cycle has this property. Here we give a common generalization. Say a “banana” is the union of a set of paths all with the same ends but otherwise disjoint. We prove that if H is obtained from a tree by replacing each edge by a banana then H has the property mentioned.
spellingShingle Scott, A
Seymour, P
Induced subgraphs of graphs with large chromatic number. VI. Banana trees
title Induced subgraphs of graphs with large chromatic number. VI. Banana trees
title_full Induced subgraphs of graphs with large chromatic number. VI. Banana trees
title_fullStr Induced subgraphs of graphs with large chromatic number. VI. Banana trees
title_full_unstemmed Induced subgraphs of graphs with large chromatic number. VI. Banana trees
title_short Induced subgraphs of graphs with large chromatic number. VI. Banana trees
title_sort induced subgraphs of graphs with large chromatic number vi banana trees
work_keys_str_mv AT scotta inducedsubgraphsofgraphswithlargechromaticnumbervibananatrees
AT seymourp inducedsubgraphsofgraphswithlargechromaticnumbervibananatrees