{ "id": "0809.0141", "version": "v2", "published": "2008-08-31T18:35:55.000Z", "updated": "2010-10-26T17:38:57.000Z", "title": "The t-stability number of a random graph", "authors": [ "Nikolaos Fountoulakis", "Ross J. Kang", "Colin McDiarmid" ], "comment": "25 pages; v2 has 30 pages and is identical to the journal version apart from formatting and a minor amendment to Lemma 8 (and its proof on p. 21)", "journal": "Electron. J. Combin. 17 (2010), #R59", "categories": [ "math.CO", "math.PR" ], "abstract": "Given a graph G = (V,E), a vertex subset S is called t-stable (or t-dependent) if the subgraph G[S] induced on S has maximum degree at most t. The t-stability number of G is the maximum order of a t-stable set in G. We investigate the typical values that this parameter takes on a random graph on n vertices and edge probability equal to p. For any fixed 0 < p < 1 and fixed non-negative integer t, we show that, with probability tending to 1 as n grows, the t-stability number takes on at most two values which we identify as functions of t, p and n. The main tool we use is an asymptotic expression for the expected number of t-stable sets of order k. We derive this expression by performing a precise count of the number of graphs on k vertices that have maximum degree at most k. Using the above results, we also obtain asymptotic bounds on the t-improper chromatic number of a random graph (this is the generalisation of the chromatic number, where we partition of the vertex set of the graph into t-stable sets).", "revisions": [ { "version": "v2", "updated": "2010-10-26T17:38:57.000Z" } ], "analyses": { "subjects": [ "05C80", "05A16" ], "keywords": [ "t-stability number", "random graph", "t-stable set", "maximum degree", "edge probability equal" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 25, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0809.0141F" } } }