{ "id": "1412.6237", "version": "v1", "published": "2014-12-19T07:40:46.000Z", "updated": "2014-12-19T07:40:46.000Z", "title": "New Bounds for the Acyclic Chromatic Index", "authors": [ "Anton Bernshteyn" ], "comment": "10 pages, 2 figures. arXiv admin note: text overlap with arXiv:1410.1591", "categories": [ "math.CO" ], "abstract": "An edge coloring of a graph $G$ is called an acyclic edge coloring if it is proper (i.e. adjacent edges receive different colors) and every cycle in $G$ contains edges of at least three different colors (there are no bichromatic cycles in $G$). The least number of colors needed for an acyclic edge coloring of $G$ is called the acyclic chromatic index of $G$ and is denoted by $a'(G)$. It is conjectured by Fiam\\v{c}ik and independently by Alon et al. that $a'(G) \\leq \\Delta(G)+2$, where $\\Delta(G)$ denotes the maximum degree of $G$. However, the best known general bound is $a'(G)\\leq 4(\\Delta(G)-1)$ due to Esperet and Parreau. We apply a generalization of the Lov\\'{a}sz Local Lemma that we call the Local Action Lemma to show that if $G$ contains no copy of a given bipartite graph $H$, then $a'(G) \\leq 3\\Delta(G)+o(\\Delta(G))$. Moreover, for every $\\varepsilon>0$ there exists a constant $c$ such that if $g(G)\\geq c$, then $a'(G)\\leq(2+\\varepsilon)\\Delta(G)+o(\\Delta(G))$, where $g(G)$ denotes the girth of $G$.", "revisions": [ { "version": "v1", "updated": "2014-12-19T07:40:46.000Z" } ], "analyses": { "keywords": [ "acyclic chromatic index", "acyclic edge coloring", "local action lemma", "bichromatic cycles", "adjacent edges" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1412.6237B" } } }