Locally identifying coloring of graphs with few P4s

Autor: Rudini Menezes Sampaio, Nícolas A. Martins
Rok vydání: 2018
Předmět:
Zdroj: Theoretical Computer Science. 707:69-76
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2017.10.015
Popis: A lid-coloring (locally identifying coloring) of a graph is a proper coloring such that, for any edge uv, if u and v have distinct closed neighborhoods, then the set of colors used on vertices of the closed neighborhoods of u and v are distinct. The lid-chromatic number is the minimum number of colors used in a lid-coloring. In this paper we prove a relation between lid-coloring and a variation, called strong lid-coloring. With this, we obtain linear time algorithms to calculate the lid-chromatic number for some classes of graphs with few P 4 's, such as cographs, P 4 -sparse graphs and ( q , q − 4 ) -graphs. We also prove that the lid-chromatic number is O ( n 1 − e ) -inapproximable in polynomial time for every e > 0 , unless P = NP .
Databáze: OpenAIRE