A proof of Frankl-Kupavskii's conjecture on edge-union condition

Hongliang Lu, Xuechun Zhang

A 3-graph $\mathcal{F}$ is \emph{$U(s,2s+1)$} if for any $s$ edges $e_1,...,e_s\in E(\mathcal{F})$, $|e_1\cup ...\cup e_s|\le 2s+1$. Frankl and Kupavskii (2020) proposed the follo…