Towards the Erdős matching conjecture for 4-uniform hypergraphs: stability and applications

Fuente: arXiv
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Main Authors: Frankl, Peter, Lu, Hongliang, Ma, Jie, Wu, Yuze
Format: Preprint
Published: 2026
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author Frankl, Peter
Lu, Hongliang
Ma, Jie
Wu, Yuze
author_facet Frankl, Peter
Lu, Hongliang
Ma, Jie
Wu, Yuze
contents A famous conjecture of Erdős asserts that for $k\ge 3$, the maximum number of edges in an $n$-vertex $k$-uniform hypergraph without $s+1$ pairwise disjoint edges is $\max\{\binom{n}{k}-\binom{n-s}{k},\binom{sk+k-1}{k}\}$. This problem has been central in extremal combinatorics, with substantial progress in the literature, including a complete solution for $k=3$ due to the first author. In this paper, we make progress towards the $4$-uniform case, proving the conjecture for $n\ge 5s$ and sufficiently large $n$, thereby taking a first step analogous to the $3$-uniform case. The main technical contribution is a stability result of independent interest. We further apply this stability to resolve two new instances of conjectures on the minimum $d$-degree threshold for matchings in $5$- and $6$-uniform hypergraphs, in a strengthened form.
format Preprint
id arxiv_https___arxiv_org_abs_2602_19230
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Towards the Erdős matching conjecture for 4-uniform hypergraphs: stability and applications
Frankl, Peter
Lu, Hongliang
Ma, Jie
Wu, Yuze
Combinatorics
A famous conjecture of Erdős asserts that for $k\ge 3$, the maximum number of edges in an $n$-vertex $k$-uniform hypergraph without $s+1$ pairwise disjoint edges is $\max\{\binom{n}{k}-\binom{n-s}{k},\binom{sk+k-1}{k}\}$. This problem has been central in extremal combinatorics, with substantial progress in the literature, including a complete solution for $k=3$ due to the first author. In this paper, we make progress towards the $4$-uniform case, proving the conjecture for $n\ge 5s$ and sufficiently large $n$, thereby taking a first step analogous to the $3$-uniform case. The main technical contribution is a stability result of independent interest. We further apply this stability to resolve two new instances of conjectures on the minimum $d$-degree threshold for matchings in $5$- and $6$-uniform hypergraphs, in a strengthened form.
title Towards the Erdős matching conjecture for 4-uniform hypergraphs: stability and applications
topic Combinatorics
url https://arxiv.org/abs/2602.19230