{ "id": "1310.4717", "version": "v1", "published": "2013-10-17T14:31:57.000Z", "updated": "2013-10-17T14:31:57.000Z", "title": "The domination number and the least $Q$-eigenvalue", "authors": [ "Guanglong Yu", "Shu-Guang Guo", "Rong Zhang", "Yarong Wu" ], "comment": "13 pages, 3 figures", "categories": [ "math.CO" ], "abstract": "A vertex set $D$ of a graph $G$ is said to be a dominating set if every vertex of $V(G)\\setminus D$ is adjacent to at least a vertex in $D$, and the domination number $\\gamma(G)$ ($\\gamma$, for short) is the minimum cardinality of all dominating sets of $G$. For a graph, the least $Q$-eigenvalue is the least eigenvalue of its signless Laplacian matrix. In this paper, for a nonbipartite graph with both order $n$ and domination number $\\gamma$, we show that $n\\geq 3\\gamma-1$, and show that it contains a unicyclic spanning subgraph with the same domination number $\\gamma$. By investigating the relation between the domination number and the least $Q$-eigenvalue of a graph, we minimize the least $Q$-eigenvalue among all the nonbipartite graphs with given domination number.", "revisions": [ { "version": "v1", "updated": "2013-10-17T14:31:57.000Z" } ], "analyses": { "subjects": [ "05C50" ], "keywords": [ "domination number", "eigenvalue", "nonbipartite graph", "dominating set", "minimum cardinality" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1310.4717Y" } } }