Intersecting families of sets are typically trivial

IF 1.2 1区 数学 Q1 MATHEMATICS Journal of Combinatorial Theory Series B Pub Date : 2023-09-20 DOI:10.1016/j.jctb.2023.09.002
József Balogh , Ramon I. Garcia , Lina Li , Adam Zsolt Wagner
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引用次数: 4

Abstract

A family of subsets of [n] is intersecting if every pair of its sets intersects. Determining the structure of large intersecting families is a central problem in extremal combinatorics. Frankl–Kupavskii and Balogh–Das–Liu–Sharifzadeh–Tran showed that for n2k+cklnk, almost all k-uniform intersecting families are stars. Improving their result, we show that the same conclusion holds for n2k+100lnk. Our proof uses, among others, the graph container method and the Das–Tran removal lemma.

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集合的相交族通常是平凡的
一个[n]的子集族是相交的,如果它的每一对集合都相交。确定大型相交族的结构是极值组合学中的一个中心问题。Frankl–Kupavskii和Balogh–Das–Liu–Sharifzadeh–Tran证明,对于n≥2k+ckln⁡k、 几乎所有k一致相交族都是恒星。改进了它们的结果,我们证明了对于n≥2k+100ln,同样的结论成立⁡k.我们的证明使用了图容器方法和Das–Tran移除引理。
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来源期刊
CiteScore
2.70
自引率
14.30%
发文量
99
审稿时长
6-12 weeks
期刊介绍: The Journal of Combinatorial Theory publishes original mathematical research dealing with theoretical and physical aspects of the study of finite and discrete structures in all branches of science. Series B is concerned primarily with graph theory and matroid theory and is a valuable tool for mathematicians and computer scientists.
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