The generalizations of Erdős matching conjecture for $t$-matching number

Fuente: arXiv
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Main Authors: Zhang, Haixiang, Cao, Mengyu, Lu, Mei
Format: Preprint
Published: 2025
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author Zhang, Haixiang
Cao, Mengyu
Lu, Mei
author_facet Zhang, Haixiang
Cao, Mengyu
Lu, Mei
contents Define a \textit{$t$-matching} of size $m$ in a $k$-uniform family as a collection $\{A_1, A_2, \ldots, A_m\} \subseteq \binom{[n]}{k}$ such that $|A_i \cap A_j| < t$ for all $1 \leq i < j \leq m$. Let $\mathcal{F}\subseteq \binom{[n]}{k}$. The \textit{$t$-matching number} of $\mathcal{F}$, denoted by $ν_t(\mathcal{F})$, is the maximum size of a $t$-matching contained in $\mathcal{F}$. We study the maximum cardinality of a family $\mathcal{F}\subseteq\binom{[n]}{k}$ with given $t$-matching number, which is a generalization of Erdős matching conjecture, and we additionally prove a stability result. We also determine the second largest maximal structure with $ν_t(\mathcal{F})=s$, extending work of Frankl and Kupavskii \cite{frankl2016two}. Finally, we obtain the extremal $G$-free induced subgraphs of generalized Kneser graph, generalizing Alishahi's results in \cite{alishahi2018extremal}.
format Preprint
id arxiv_https___arxiv_org_abs_2508_12679
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The generalizations of Erdős matching conjecture for $t$-matching number
Zhang, Haixiang
Cao, Mengyu
Lu, Mei
Combinatorics
05C35, 05D05, 05D15
Define a \textit{$t$-matching} of size $m$ in a $k$-uniform family as a collection $\{A_1, A_2, \ldots, A_m\} \subseteq \binom{[n]}{k}$ such that $|A_i \cap A_j| < t$ for all $1 \leq i < j \leq m$. Let $\mathcal{F}\subseteq \binom{[n]}{k}$. The \textit{$t$-matching number} of $\mathcal{F}$, denoted by $ν_t(\mathcal{F})$, is the maximum size of a $t$-matching contained in $\mathcal{F}$. We study the maximum cardinality of a family $\mathcal{F}\subseteq\binom{[n]}{k}$ with given $t$-matching number, which is a generalization of Erdős matching conjecture, and we additionally prove a stability result. We also determine the second largest maximal structure with $ν_t(\mathcal{F})=s$, extending work of Frankl and Kupavskii \cite{frankl2016two}. Finally, we obtain the extremal $G$-free induced subgraphs of generalized Kneser graph, generalizing Alishahi's results in \cite{alishahi2018extremal}.
title The generalizations of Erdős matching conjecture for $t$-matching number
topic Combinatorics
05C35, 05D05, 05D15
url https://arxiv.org/abs/2508.12679