Frankl–Kupavskii weighted-construction conjecture for the Erdős–Kleitman problem

From papers

Let [n]={1,2,,n}[n]=\{1,2,\ldots,n\}, let e(n,s)e(n,s) be the maximum of F|\mathcal F| over families F2[n]\mathcal F\subseteq 2^{[n]} with matching number ν(F)<s\nu(\mathcal F)<s, and, for a weight function w ⁣:[n]R0w\colon[n]\to\mathbb R_{\ge0}, define

F(w)={F[n] ⁣:xFw(x)1}.\mathcal F(w)=\left\{F\subseteq[n]\colon\sum_{x\in F}w(x)\ge1\right\}.

If i=1nw(i)<s\sum_{i=1}^n w(i)<s, then ν(F(w))<s\nu(\mathcal F(w))<s. Frankl–Kupavskii conjecture. For any n,sn,s, the maximum in the definition of e(n,s)e(n,s) is attained by a family F(w)\mathcal F(w) for some w ⁣:[n]R0w\colon[n]\to\mathbb R_{\ge0}. This meta-conjecture would reduce the Erdős–Kleitman extremal problem to weighted constructions; its resolution is not specified in the source.

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Sources & referencesView supporting material

Primary source

Cheng Chi and Yan Wang, “Extremal Families for the Erdős–Kleitman Problem: The Missing Constructions”, arXiv:2607.25611 (2026).

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