An approximate version of Hadwiger's conjecture for claw‐free graphs

Autor: Chudnovsky, Maria, Fradkin, Alexandra Ovetsky
Zdroj: Journal of Graph Theory; April 2010, Vol. 63 Issue: 4 p259-278, 20p
Abstrakt: Hadwiger's conjecture states that every graph with chromatic number χ has a clique minor of size χ. In this paper we prove a weakened version of this conjecture for the class of claw‐free graphs (graphs that do not have a vertex with three pairwise nonadjacent neighbors). Our main result is that a claw‐free graph with chromatic number χ has a clique minor of size \documentclass{article}\usepackage{amssymb}\usepackage{amsbsy}\usepackage[mathscr]{euscript}\footskip=0pc\pagestyle{empty}\begin{document}$\lceil\frac{2}{3}\chi\rceil$\end{document}. © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 259–278, 2010
Databáze: Supplemental Index