Generalized Ramsey–Turán density for cliques

We study the generalized Ramsey–Turán function $\mathrm {RT}(n,K_s,K_t,o(n))$ , which is the maximum possible number of copies of $K_s$ in an n-vertex $K_t$ -free graph with independence number $o(n)$ . The case when $s=2$ was settled by Erdős, Sós, Bollobás, Hajnal,...

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Bibliographic Details
Main Authors: Jun Gao, Suyun Jiang, Hong Liu, Maya Sankar
Format: Article
Language:English
Published: Cambridge University Press 2025-01-01
Series:Forum of Mathematics, Sigma
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Online Access:https://www.cambridge.org/core/product/identifier/S2050509425000295/type/journal_article
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Summary:We study the generalized Ramsey–Turán function $\mathrm {RT}(n,K_s,K_t,o(n))$ , which is the maximum possible number of copies of $K_s$ in an n-vertex $K_t$ -free graph with independence number $o(n)$ . The case when $s=2$ was settled by Erdős, Sós, Bollobás, Hajnal, and Szemerédi in the 1980s. We combinatorially resolve the general case for all $s\ge 3$ , showing that the (asymptotic) extremal graphs for this problem have simple (bounded) structures. In particular, it implies that the extremal structures follow a periodic pattern when t is much larger than s. Our results disprove a conjecture of Balogh, Liu, and Sharifzadeh and show that a relaxed version does hold.
ISSN:2050-5094