Acyclic chromatic index of triangle-free 1-planar graphs
arXiv:1504.06234 · doi:10.1007/s00373-017-1809-0
Abstract
An acyclic edge coloring of a graph is a proper edge coloring such that every cycle is colored with at least three colors. The acyclic chromatic index $\chiup_{a}'(G)$ of a graph is the least number of colors in an acyclic edge coloring of . It was conjectured that $\chiup'_{a}(G)\leq Δ(G) + 2$ for any simple graph with maximum degree . A graph is {\em -planar} if it can be drawn on the plane such that every edge is crossed by at most one other edge. In this paper, we prove that every triangle-free -planar graph has an acyclic edge coloring with colors.
7 pages. Lemma 6 was strengthened and the main result was slightly improved