{ "id": "1908.06679", "version": "v1", "published": "2019-08-19T10:09:56.000Z", "updated": "2019-08-19T10:09:56.000Z", "title": "The 3-way flower intersection problem for Steiner triple systems", "authors": [ "H. Amjadi", "N. Soltankhah" ], "comment": "14 pages", "categories": [ "math.CO" ], "abstract": "The flower at a point x in a Steiner triple system (X; B) is the set of all triples containing x. Denote by J3F(r) the set of all integers k such that there exists a collection of three STS(2r+1) mutually intersecting in the same set of k + r triples, r of them being the triples of a common flower. In this article we determine the set J3F(r) for any positive integer r = 0, 1 (mod 3) (only some cases are left undecided for r = 6, 7, 9, 24), and establish that J3F(r) = I3F(r) for r = 0, 1 (mod 3) where I3F(r) = {0, 1,..., 2r(r-1)/3-8, 2r(r-1)/3-6, 2r(r-1)/3}.", "revisions": [ { "version": "v1", "updated": "2019-08-19T10:09:56.000Z" } ], "analyses": { "subjects": [ "05B05" ], "keywords": [ "steiner triple system", "flower intersection problem", "common flower", "set j3f", "positive integer" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }