{ "id": "2002.00765", "version": "v1", "published": "2020-01-30T23:11:59.000Z", "updated": "2020-01-30T23:11:59.000Z", "title": "New upper bounds for the bondage number of a graph in terms of its maximum degree and Euler characteristic", "authors": [ "Jia Huang", "Jian Shen" ], "comment": "11 pages. arXiv admin note: text overlap with arXiv:1111.5629", "journal": "Ars Combinatoria 140 (2018) 373--387", "categories": [ "math.CO" ], "abstract": "The bondage number $b(G)$ of a graph $G$ is the smallest number of edges whose removal from $G$ results in a graph with larger domination number. Let $G$ be embeddable on a surface whose Euler characteristic $\\chi$ is as large as possible, and assume $\\chi\\leq0$. Gagarin-Zverovich and Huang have recently found upper bounds of $b(G)$ in terms of the maximum degree $\\Delta(G)$ and the Euler characteristic $\\chi(G)=\\chi$. In this paper we prove a better upper bound $b(G)\\leq\\Delta(G)+\\lfloor t\\rfloor$ where $t$ is the largest real root of the cubic equation $z^3 + z^2 + (3\\chi - 8)z + 9\\chi - 12=0$; this upper bound is asymptotically equivalent to $b(G)\\leq\\Delta(G)+1+\\lfloor \\sqrt{4-3\\chi} \\rfloor$. We also establish further improved upper bounds for $b(G)$ when the girth, order, or size of the graph $G$ is large compared with its Euler characteristic $\\chi$.", "revisions": [ { "version": "v1", "updated": "2020-01-30T23:11:59.000Z" } ], "analyses": { "keywords": [ "euler characteristic", "maximum degree", "bondage number", "largest real root", "larger domination number" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }