{ "id": "1608.03314", "version": "v1", "published": "2016-08-10T23:57:58.000Z", "updated": "2016-08-10T23:57:58.000Z", "title": "On symmetric 3-wise intersecting families", "authors": [ "David Ellis", "Bhargav Narayanan" ], "comment": "7 pages", "categories": [ "math.CO" ], "abstract": "A family of sets is said to be {\\em symmetric} if its automorphism group is transitive, and {\\em $3$-wise intersecting} if any three sets in the family have nonempty intersection. Frankl conjectured in 1981 that if $\\mathcal{A}$ is a symmetric $3$-wise intersecting family of subsets of $\\{1,2,\\ldots,n\\}$, then $|\\mathcal{A}| = o(2^n)$. Here, we give a short proof of Frankl's conjecture, using a `sharp threshold' result of Friedgut and Kalai.", "revisions": [ { "version": "v1", "updated": "2016-08-10T23:57:58.000Z" } ], "analyses": { "subjects": [ "05D05" ], "keywords": [ "intersecting family", "automorphism group", "nonempty intersection", "short proof", "frankls conjecture" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable" } } }