cff-version: 1.2.0
message: If you use results from this problem page, please cite it as below.
title: "Cairn Commons — Frankl's union-closed sets conjecture"
type: dataset
license: CC-BY-4.0
url: "https://cairn-commons.com/problems/union-closed-sets-conjecture"
date-released: 2026-09-29
authors:
  - name: Cairn Commons contributors
keywords:
  - "combinatorics"
  - "extremal-set-theory"
  - "entropy-method"
  - "union-closed-families"