2 research outputs found
Every 4-regular graph is acyclically edge-6-colorable
An acyclic edge coloring of a graph is a proper edge coloring such that
no bichromatic cycles are produced. The acyclic chromatic index of
is the smallest integer such that has an acyclic edge coloring using
colors. Fiamik (1978) and later Alon, Sudakov and Zaks
(2001) conjectured that for any simple graph with
maximum degree . Basavaraju and Chandran (2009) showed that every graph
with , which is not 4-regular, satisfies the conjecture. In this
paper, we settle the 4-regular case, i.e., we show that every 4-regular graph
has .Comment: 24 pages, 9 figure
A new upper bound on the acyclic chromatic indices of planar graphs
An acyclic edge coloring of a graph is a proper edge coloring such that
no bichromatic cycles are produced. The acyclic chromatic index of
is the smallest integer such that has an acyclic edge coloring using
colors. It was conjectured that for any simple graph
with maximum degree . In this paper, we prove that if is a
planar graph, then . This improves a result by Basavaraju
et al. [{\em Acyclic edge-coloring of planar graphs}, SIAM J. Discrete Math.,
25 (2011), pp. 463-478], which says that every planar graph satisfies
.Comment: 23 pages, 1 figure