{ "id": "1609.03002", "version": "v1", "published": "2016-09-10T05:48:35.000Z", "updated": "2016-09-10T05:48:35.000Z", "title": "Radio number of trees", "authors": [ "Devsi Bantva", "Samir Vaidya", "Sanming Zhou" ], "comment": "19 pages, 7 figures. This is the final version accepted in Discrete Applied Mathematics", "categories": [ "math.CO" ], "abstract": "A radio labeling of a graph $G$ is a mapping $f: V(G) \\rightarrow \\{0, 1, 2, \\ldots\\}$ such that $|f(u)-f(v)|\\geq d + 1 - d(u,v)$ for every pair of distinct vertices $u, v$ of $G$, where $d$ is the diameter of $G$ and $d(u,v)$ the distance between $u$ and $v$ in $G$. The radio number of $G$ is the smallest integer $k$ such that $G$ has a radio labeling $f$ with $\\max\\{f(v) : v \\in V(G)\\} = k$. We give a necessary and sufficient condition for a lower bound on the radio number of trees to be achieved, two other sufficient conditions for the same bound to be achieved by a tree, and an upper bound on the radio number of trees. Using these, we determine the radio number for three families of trees.", "revisions": [ { "version": "v1", "updated": "2016-09-10T05:48:35.000Z" } ], "analyses": { "subjects": [ "05C78", "05C15" ], "keywords": [ "radio number", "sufficient condition", "radio labeling", "distinct vertices", "lower bound" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable" } } }