Stability of intersecting families
Abstract
The celebrated Erd\H{o}s-Ko-Rado theorem \cite{EKR1961} states that the maximum intersecting -uniform family on is a full star if . Furthermore, Hilton-Milner \cite{HM1967} showed that if an intersecting -uniform family on is not a subfamily of a full star, then its maximum size achieves only on a family isomorphic to if and , and there is one more possibility in the case of . Han and Kohayakawa \cite{HK2017} determined the maximum intersecting -uniform family on which is neither a subfamily of a full star nor a subfamily of the extremal family in Hilton-Milner theorm, and they asked what is the next maximum intersecting -uniform family on . Kostochka and Mubayi \cite{KM2016} gave the answer for large enough . In this paper, we are going to get rid of the requirement that is large enough in the result by Kostochka and Mubayi \cite{KM2016} and answer the question of Han and Kohayakawa \cite{HK2017}.
Keywords
Cite
@article{arxiv.2205.05394,
title = {Stability of intersecting families},
author = {Yang Huang and Yuejian Peng},
journal= {arXiv preprint arXiv:2205.05394},
year = {2022}
}
Comments
28 pages, 1 figure