Uniform set systems with small VC-dimension and the Erdős--Ko--Rado theorem

Series
Combinatorics Seminar
Time
Friday, February 14, 2025 - 3:15pm for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Chi Hoi (Kyle) Yip – Georgia Institute of Technology – cyip30@gatech.eduhttps://sites.google.com/view/kyle-chi-hoi-yip/home
Organizer
Xiaoyu He, Tom Kelly, Jiaxi Nie

Let $d\geq 2$, and $n\geq 2d+2$. Frankl and Pach initiated the study of the maximum size of a $(d+1)$-uniform set system in $[n]$ with VC-dimension at most $d$. The best-known upper bound is essentially $\binom{n}{d}$, and the best-known lower bound is $\binom{n-1}{d} + \binom{n-4}{d-2}$. In this talk, I will discuss some recent improvements on the upper bound and some interesting connections between this problem and the celebrated Erdős--Ko--Rado theorem. In particular, I will discuss our conjecture, which can be viewed as a generalization of the EKR as well as an "uniform version" of the disproved Erdős--Frankl--Pach conjecture, and highlight some of our partial progress. Joint work with Ting-Wei Chao, Zixiang Xu, and Shengtong Zhang.