{ "id": "1109.3930", "version": "v1", "published": "2011-09-19T02:54:33.000Z", "updated": "2011-09-19T02:54:33.000Z", "title": "Roman Bondage Number of a Graph", "authors": [ "Fu-Tao Hu", "Jun-Ming Xu" ], "comment": "21 pages with 1 figures", "categories": [ "math.CO" ], "abstract": "The Roman dominating function on a graph $G=(V,E)$ is a function $f: V\\rightarrow\\{0,1,2\\}$ such that each vertex $x$ with $f(x)=0$ is adjacent to at least one vertex $y$ with $f(y)=2$. The value $f(G)=\\sum\\limits_{u\\in V(G)} f(u)$ is called the weight of $f$. The Roman domination number $\\gamma_{\\rm R}(G)$ is defined as the minimum weight of all Roman dominating functions. This paper defines the Roman bondage number $b_{\\rm R}(G)$ of a nonempty graph $G=(V,E)$ to be the cardinality among all sets of edges $B\\subseteq E$ for which $\\gamma_{\\rm R}(G-B)>\\gamma_{\\rm R}(G)$. Some bounds are obtained for $b_{\\rm R}(G)$, and the exact values are determined for several classes of graphs. Moreover, the decision problem for $b_{\\rm R}(G)$ is proved to be NP-hard even for bipartite graphs.", "revisions": [ { "version": "v1", "updated": "2011-09-19T02:54:33.000Z" } ], "analyses": { "subjects": [ "05C69", "E.1", "G.2.2" ], "keywords": [ "roman bondage number", "roman dominating function", "roman domination number", "decision problem", "exact values" ], "note": { "typesetting": "TeX", "pages": 21, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1109.3930H" } } }