English

Claw-free graphs, skeletal graphs, and a stronger conjecture on $\omega$, $\Delta$, and $\chi$

Discrete Mathematics 2012-12-14 v1 Combinatorics

Abstract

The second author's ω\omega, Δ\Delta, χ\chi conjecture proposes that every graph satisties χ12(Δ+1+ω)\chi \leq \lceil \frac 12 (\Delta+1+\omega)\rceil. In this paper we prove that the conjecture holds for all claw-free graphs. Our approach uses the structure theorem of Chudnovsky and Seymour. Along the way we discuss a stronger local conjecture, and prove that it holds for claw-free graphs with a three-colourable complement. To prove our results we introduce a very useful χ\chi-preserving reduction on homogeneous pairs of cliques, and thus restrict our view to so-called "skeletal" graphs.

Keywords

Cite

@article{arxiv.1212.3036,
  title  = {Claw-free graphs, skeletal graphs, and a stronger conjecture on $\omega$, $\Delta$, and $\chi$},
  author = {Andrew D. King and Bruce A. Reed},
  journal= {arXiv preprint arXiv:1212.3036},
  year   = {2012}
}

Comments

32 pages, 6 figures