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Large cliques or cocliques in hypergraphs with forbidden order-size pairs

Axenovich, Maria 1; Bradač, Domagoj; Gishboliner, Lior; Mubayi, Dhruv; Weber, Lea 1
1 Institut für Algebra und Geometrie (IAG), Karlsruher Institut für Technologie (KIT)

Abstract:

The well-known Erdős-Hajnal conjecture states that for any graph F, there exists ϵ>0 such that every n-vertex graph G that contains no induced copy of F has a homogeneous set of size at least nϵ. We consider a variant of the Erdős-Hajnal problem for hypergraphs where we forbid a family of hypergraphs described by their orders and sizes. For graphs, we observe that if we forbid induced subgraphs on m vertices and f edges for any positive m and 0f(m2), then we obtain large homogeneous sets. For triple systems, in the first nontrivial case m=4, for every S0,1,2,3,4, we give bounds on the minimum size of a homogeneous set in a triple system where the number of edges spanned by every four vertices is not in S. In most cases the bounds are essentially tight. We also determine, for all S, whether the growth rate is polynomial or polylogarithmic. Some open problems remain.

Zugehörige Institution(en) am KIT Institut für Algebra und Geometrie (IAG)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2024
Sprache Englisch
Identifikator ISSN: 0963-5483, 1469-2163
KITopen-ID: 1000167010
Erschienen in Combinatorics, Probability and Computing
Verlag Cambridge University Press (CUP)
Band 33
Heft 3
Seiten 286-299
Vorab online veröffentlicht am 16.11.2023
Schlagwörter Erdős-Hajnal conjecture, homogeneous sets in hypergraphs
Nachgewiesen in Scopus
OpenAlex
Web of Science
Dimensions

Verlagsausgabe §
DOI: 10.5445/IR/1000167010
Veröffentlicht am 08.01.2024
Originalveröffentlichung
DOI: 10.1017/S0963548323000433
Scopus
Zitationen: 2
Web of Science
Zitationen: 2
Dimensions
Zitationen: 2
Seitenaufrufe: 40
seit 08.01.2024
Downloads: 21
seit 08.01.2024
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