{ "id": "1302.7313", "version": "v1", "published": "2013-02-28T20:50:16.000Z", "updated": "2013-02-28T20:50:16.000Z", "title": "A new proof for the Erdős-Ko-Rado Theorem for the alternating group", "authors": [ "Bahman Ahmadi", "Karen Meagher" ], "comment": "23 pages", "categories": [ "math.CO" ], "abstract": "A subset $S$ of the alternating group on $n$ points is {\\it intersecting} if for any pair of permutations $\\pi,\\sigma$ in $S$, there is an element $i\\in \\{1,\\dots,n\\}$ such that $\\pi(i)=\\sigma(i)$. We prove that if $S$ is intersecting, then $|S|\\leq \\frac{(n-1)!}{2}$. Also, we prove that if $n \\geq 5$, then the only sets $S$ that meet this bound are the cosets of the stabilizer of a point of $\\{1,\\dots,n\\}$.", "revisions": [ { "version": "v1", "updated": "2013-02-28T20:50:16.000Z" } ], "analyses": { "subjects": [ "05C35", "05C69" ], "keywords": [ "alternating group", "erdős-ko-rado theorem", "permutations", "stabilizer" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1302.7313A" } } }