{ "id": "1310.1643", "version": "v5", "published": "2013-10-06T22:56:18.000Z", "updated": "2014-12-12T16:47:18.000Z", "title": "On the Erdos-Ko-Rado property for finite Groups", "authors": [ "Mohammad Bardestani", "Keivan Mallahi-Karai" ], "comment": "This is the final version. To appear in the Journal of Algebraic Combinatorics", "categories": [ "math.GR", "math.CO" ], "abstract": "Let a finite group $G$ act transitively on a finite set $X$. A subset $S\\subseteq G$ is said to be {\\it intersecting} if for any $s_1,s_2\\in S$, the element $s_1^{-1}s_2$ has a fixed point. The action is said to have the {\\it weak Erd\\H{o}s-Ko-Rado} property, if the cardinality of any intersecting set is at most $|G|/|X|$. If, moreover, any maximal intersecting set is a coset of a point stabilizer, the action is said to have the {\\it strong Erd\\H{o}s-Ko-Rado} property. In this paper we will investigate the weak and strong Erd\\H{o}s-Ko-Rado property and attempt to classify the groups whose all transitive actions have these properties. In particular, we show that a group with the weak Erd\\H{o}s-Ko-Rado property is solvable and that a nilpotent group with the strong Erd\\H{o}s-Ko-Rado property is product of a $2$-group and an abelian group of odd order.", "revisions": [ { "version": "v4", "updated": "2014-01-09T22:35:45.000Z", "comment": "Paper is reorganized. Theorem 1 is improved and a new corrected proof is given", "journal": null, "doi": null }, { "version": "v5", "updated": "2014-12-12T16:47:18.000Z" } ], "analyses": { "keywords": [ "finite group", "erdos-ko-rado property", "finite set", "maximal intersecting set", "point stabilizer" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1310.1643B" } } }