On the $\ell$-th largest degree of an intersecting family
Combinatorics
2026-04-22 v3
Abstract
Let be an intersecting family. For an element , the degree of is the number of sets in that contain . Assume that the degrees are ordered as .Huang and Zhao showed that if , then the minimum degree satisfies , with the maximum attained by the -star. We strengthen this result by proving that for , the -th largest degree satisfies , thereby confirming a conjecture of Frankl and Wang. Furthermore, we prove that for large and , the -th largest degree is already at most . The techniques we developed also yield a tight upper bound for the -th largest degree for and sufficiently large .
Keywords
Cite
@article{arxiv.2602.01692,
title = {On the $\ell$-th largest degree of an intersecting family},
author = {Hao Huang and Rui Rao},
journal= {arXiv preprint arXiv:2602.01692},
year = {2026}
}