{ "id": "1203.3030", "version": "v1", "published": "2012-03-14T09:35:41.000Z", "updated": "2012-03-14T09:35:41.000Z", "title": "Note on minimally $k$-rainbow connected graphs", "authors": [ "Hengzhe Li", "Xueliang Li", "Yuefang Sun", "Yan Zhao" ], "comment": "8 pages", "categories": [ "math.CO" ], "abstract": "An edge-colored graph $G$, where adjacent edges may have the same color, is {\\it rainbow connected} if every two vertices of $G$ are connected by a path whose edge has distinct colors. A graph $G$ is {\\it $k$-rainbow connected} if one can use $k$ colors to make $G$ rainbow connected. For integers $n$ and $d$ let $t(n,d)$ denote the minimum size (number of edges) in $k$-rainbow connected graphs of order $n$. Schiermeyer got some exact values and upper bounds for $t(n,d)$. However, he did not get a lower bound of $t(n,d)$ for $3\\leq d<\\lceil\\frac{n}{2}\\rceil $. In this paper, we improve his lower bound of $t(n,2)$, and get a lower bound of $t(n,d)$ for $3\\leq d<\\lceil\\frac{n}{2}\\rceil$.", "revisions": [ { "version": "v1", "updated": "2012-03-14T09:35:41.000Z" } ], "analyses": { "subjects": [ "05C15", "05C35", "05C40" ], "keywords": [ "rainbow connected graphs", "lower bound", "adjacent edges", "upper bounds", "distinct colors" ], "note": { "typesetting": "TeX", "pages": 8, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1203.3030L" } } }