{ "id": "1301.1521", "version": "v2", "published": "2013-01-08T13:24:41.000Z", "updated": "2013-06-05T14:53:57.000Z", "title": "On the excessive [m]-index of a tree", "authors": [ "Giuseppe Mazzuoccolo" ], "comment": "12 pages, 7 figures, to appear in Discrete Applied Mathematics", "categories": [ "math.CO" ], "abstract": "The excessive [m]-index of a graph G is the minimum number of matchings of size m needed to cover the edge-set of G. We call a graph G [m]-coverable if its excessive [m]-index is finite. Obviously the excessive [1]-index is |E(G)| for all graphs and it is an easy task the computation of the excessive [2]-index for a [2]-coverable graph. The case m=3 is completely solved by Cariolaro and Fu in 2009. In this paper we prove a general formula to compute the excessive [4]-index of a tree and we conjecture a possible generalization for any value of m. Furthermore, we prove that such a formula does not work for the excessive [4]-index of an arbitrary graph.", "revisions": [ { "version": "v2", "updated": "2013-06-05T14:53:57.000Z" } ], "analyses": { "subjects": [ "05C70", "05C15" ], "keywords": [ "minimum number", "general formula", "arbitrary graph", "computation", "conjecture" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1301.1521M" } } }