{ "id": "1012.1942", "version": "v2", "published": "2010-12-09T08:56:17.000Z", "updated": "2012-03-05T05:54:03.000Z", "title": "On Rainbow-$k$-Connectivity of Random Graphs", "authors": [ "Jing He", "Hongyu Liang" ], "categories": [ "math.CO", "cs.DM" ], "abstract": "A path in an edge-colored graph is called a \\emph{rainbow path} if all edges on it have pairwise distinct colors. For $k\\geq 1$, the \\emph{rainbow-$k$-connectivity} of a graph $G$, denoted $rc_k(G)$, is the minimum number of colors required to color the edges of $G$ in such a way that every two distinct vertices are connected by at least $k$ internally disjoint rainbow paths. In this paper, we study rainbow-$k$-connectivity in the setting of random graphs. We show that for every fixed integer $d\\geq 2$ and every $k\\leq O(\\log n)$, $p=\\frac{(\\log n)^{1/d}}{n^{(d-1)/d}}$ is a sharp threshold function for the property $rc_k(G(n,p))\\leq d$. This substantially generalizes a result due to Caro et al., stating that $p=\\sqrt{\\frac{\\log n}{n}}$ is a sharp threshold function for the property $rc_1(G(n,p))\\leq 2$. As a by-product, we obtain a polynomial-time algorithm that makes $G(n,p)$ rainbow-$k$-connected using at most one more than the optimal number of colors with probability $1-o(1)$, for all $k\\leq O(\\log n)$ and $p=n^{-\\epsilon(1\\pm o(1))}$ for some constant $\\epsilon\\in[0,1)$.", "revisions": [ { "version": "v2", "updated": "2012-03-05T05:54:03.000Z" } ], "analyses": { "keywords": [ "random graphs", "connectivity", "sharp threshold function", "internally disjoint rainbow paths", "distinct vertices" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1012.1942H" } } }