Full-range low-degree vertex conjecture for intersecting hypergraphs

Let [n]={1,2,,n}[n]=\{1,2,\ldots,n\}, and let F([n]k)\mathcal{F}\subset \binom{[n]}{k} be an intersecting family, meaning that any two members of F\mathcal{F} intersect. The degree of a vertex is the number of members of F\mathcal{F} containing it.

Full-range low-degree vertex conjecture. If n>2kn>2k, then at least n2kn-2k vertices have degree at most

(n2k2).\binom{n-2}{k-2}.

The paper proves this conclusion under the stronger hypothesis n6kn\geq 6k, while the Huang–Zhao theorem gives one such vertex for n>2kn>2k. The conjecture asks whether the bound of n2kn-2k vertices holds throughout the full range n>2kn>2k.

Sources & referencesView supporting material

Primary source

Peter Frankl and Jian Wang, “On the largest degrees in intersecting hypergraphs”, arXiv:2511.15508 (2025).

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