{ "id": "1208.4734", "version": "v1", "published": "2012-08-23T12:10:08.000Z", "updated": "2012-08-23T12:10:08.000Z", "title": "New approach to the $k$-independence number of a graph", "authors": [ "Yair Caro", "Adriana Hansberg" ], "comment": "16 pages", "categories": [ "math.CO" ], "abstract": "Let $G = (V,E)$ be a graph and $k \\ge 0$ an integer. A $k$-independent set $S \\subseteq V$ is a set of vertices such that the maximum degree in the graph induced by $S$ is at most $k$. With $\\alpha_k(G)$ we denote the maximum cardinality of a $k$-independent set of $G$. We prove that, for a graph $G$ on $n$ vertices and average degree $d$, $\\alpha_k(G) \\ge \\frac{k+1}{\\lceil d \\rceil + k + 1} n$, improving the hitherto best general lower bound due to Caro and Tuza [Improved lower bounds on k-independence, J. Graph Theory 15 (1991), 99-107].", "revisions": [ { "version": "v1", "updated": "2012-08-23T12:10:08.000Z" } ], "analyses": { "subjects": [ "05C69" ], "keywords": [ "independence number", "hitherto best general lower bound", "independent set", "maximum degree", "maximum cardinality" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1208.4734C" } } }