Degree versions of theorems on intersecting families via stability

TL;DR

This paper extends classical theorems on intersecting families of sets by providing degree and t-degree versions, and broadens the parameter range where the Erdős Matching Conjecture holds, advancing combinatorial set theory.

Contribution

It introduces degree and t-degree variants of the Erdős-Ko-Rado and Hilton-Milner theorems, and extends the validity range of the Erdős Matching Conjecture.

Findings

Degree versions of Erdős-Ko-Rado and Hilton-Milner theorems established.

Extended the range where the Erdős Matching Conjecture holds.

Generalized previous results by Huang, Zhao, Frankl, and others.

Abstract

The matching number of a family of subsets of an $n$-element set is the maximum number of pairwise disjoint sets. The families with matching number $1$ are called intersecting. The famous Erd\H os-Ko-Rado theorem determines the size of the largest intersecting family of $k$-sets. Its generalization to the families with larger matching numbers, known under the name of the Erd\H{o}s Matching Conjecture, is still open for a wide range of parameters. In this paper, we address the degree versions of both theorems. More precisely, we give degree and $t$-degree versions of the Erd\H{o}s-Ko-Rado and the Hilton-Milner theorems, extending the results of Huang and Zhao, and Frankl, Han, Huang and Zhao. We also extend the range in which the degree version of the Erd\H{o}s Matching conjecture holds.