{ "id": "math/0306119", "version": "v1", "published": "2003-06-06T12:52:00.000Z", "updated": "2003-06-06T12:52:00.000Z", "title": "The number of k-intersections of an intersecting family of r-sets", "authors": [ "John Talbot" ], "comment": "10 pages, 1 figure", "categories": [ "math.CO" ], "abstract": "The Erdos-Ko-Rado theorem tells us how large an intersecting family of r-sets from an n-set can be, while results due to Lovasz and Tuza give bounds on the number of singletons that can occur as pairwise intersections of sets from such a family. We consider a natural generalization of these problems. Given an intersecting family of r-sets from an n-set and 1\\leq k \\leq r, how many k-sets can occur as pairwise intersections of sets from the family? For k=r and k=1 this reduces to the problems described above. We answer this question exactly for all values of k and r, when n is sufficiently large. We also characterize the extremal families.", "revisions": [ { "version": "v1", "updated": "2003-06-06T12:52:00.000Z" } ], "analyses": { "subjects": [ "05D05" ], "keywords": [ "intersecting family", "k-intersections", "erdos-ko-rado theorem tells", "pairwise intersections", "extremal families" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2003math......6119T" } } }