{ "id": "1111.4493", "version": "v1", "published": "2011-11-18T21:27:32.000Z", "updated": "2011-11-18T21:27:32.000Z", "title": "An Erdős-Ko-Rado theorem for multisets", "authors": [ "Karen Meagher", "Alison Purdy" ], "comment": "8 pages", "journal": "Electron. J. Combin. 18 (2011), no.1, Paper 220, 8 pp", "categories": [ "math.CO" ], "abstract": "Let $k$ and $m$ be positive integers. A collection of $k$-multisets from $\\{1,..., m \\}$ is intersecting if every pair of multisets from the collection is intersecting. We prove that for $m \\geq k+1$, the size of the largest such collection is $\\binom{m+k-2}{k-1}$ and that when $m > k+1$, only a collection of all the $k$-multisets containing a fixed element will attain this bound. The size and structure of the largest intersecting collection of $k$-multisets for $m \\leq k$ is also given.", "revisions": [ { "version": "v1", "updated": "2011-11-18T21:27:32.000Z" } ], "analyses": { "subjects": [ "05D05" ], "keywords": [ "erdős-ko-rado theorem", "largest intersecting collection", "positive integers", "fixed element" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 8, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1111.4493M" } } }