{ "id": "1504.00769", "version": "v1", "published": "2015-04-03T08:02:09.000Z", "updated": "2015-04-03T08:02:09.000Z", "title": "The maximal length of a gap between r-graph Turán densities", "authors": [ "Oleg Pikhurko" ], "comment": "7 pages", "categories": [ "math.CO" ], "abstract": "The Tur\\'an density $\\pi(\\cal F)$ of a family $\\cal F$ of $r$-graphs is the limit as $n\\to\\infty$ of the maximum edge density of an $\\cal F$-free $r$-graph on $n$ vertices. Erdos [Israel J. Math 2 (1964) 183--190] proved that no Tur\\'an density can lie in the open interval $(0,r!/r^r)$. Here we show that any other open subinterval of $[0,1]$ avoiding Tur\\'an densities has strictly smaller length. In particular, this implies a conjecture of Grosu [E-print arXiv:1403.4653v1, 2014].", "revisions": [ { "version": "v1", "updated": "2015-04-03T08:02:09.000Z" } ], "analyses": { "subjects": [ "05D05" ], "keywords": [ "r-graph turán densities", "maximal length", "turan density", "maximum edge density", "open interval" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150400769P" } } }