{ "id": "1310.6766", "version": "v1", "published": "2013-10-24T20:28:25.000Z", "updated": "2013-10-24T20:28:25.000Z", "title": "Extremal numbers for odd cycles", "authors": [ "Zoltan Füredi", "David S. Gunderson" ], "comment": "6 pages", "categories": [ "math.CO" ], "abstract": "We describe the C_{2k+1}-free graphs on n vertices with maximum number of edges. The extremal graphs are unique except for n = 3k-1, 3k, 4k-2, or 4k-1. The value of ex(n,C_{2k+1}) can be read out from the works of Bondy, Woodall, and Bollobas, but here we give a new streamlined proof. The complete determination of the extremal graphs is also new. We obtain that the bound for n_0(C_{2k+1}) is 4k in the classical theorem of Simonovits, from which the unique extremal graph is the bipartite Turan graph.", "revisions": [ { "version": "v1", "updated": "2013-10-24T20:28:25.000Z" } ], "analyses": { "subjects": [ "05C35", "05D99" ], "keywords": [ "odd cycles", "extremal numbers", "bipartite turan graph", "unique extremal graph", "maximum number" ], "note": { "typesetting": "TeX", "pages": 6, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1310.6766F" } } }