2 research outputs found
Injective edge-coloring of sparse graphs
An injective edge-coloring of a graph is an edge-coloring such that
if , , and are three consecutive edges in (they are
consecutive if they form a path or a cycle of length three), then and
receive different colors. The minimum integer such that, has an
injective edge-coloring with colors, is called the injective chromatic
index of (). This parameter was introduced by
Cardoso et \textit{al.} \cite{CCCD} motivated by the Packet Radio Network
problem. They proved that computing of a graph is
NP-hard. We give new upper bounds for this parameter and we present the
relationships of the injective edge-coloring with other colorings of graphs.
The obtained general bound gives 8 for the injective chromatic index of a
subcubic graph. If the graph is subcubic bipartite we improve this last bound.
We prove that a subcubic bipartite graph has an injective chromatic index
bounded by . We also prove that if is a subcubic graph with maximum
average degree less than (resp. , ), then
admits an injective edge-coloring with at most 4 (resp. , ) colors.
Moreover, we establish a tight upper bound for subcubic outerplanar graphs
Injective edge-coloring of graphs with given maximum degree
A coloring of edges of a graph is injective if for any two distinct edges
and , the colors of and are distinct if they are at
distance in or in a common triangle. Naturally, the injective chromatic
index of , , is the minimum number of colors needed for an
injective edge-coloring of . We study how large can be the injective
chromatic index of in terms of maximum degree of when we have
restrictions on girth and/or chromatic number of . We also compare our
bounds with analogous bounds on the strong chromatic index.Comment: 13 page