Circular chromatic number of triangle free
graphs with given maximum average degree,
extended abstract.
Andr´ e Raspaud
LaBRI
Universit´ e Bordeaux I, Talence, France
raspaud@labri.fr
Nicolas Roussel
1
National Sun Yat-Sen University
Kaohsiung, Taiwan
roussel@labri.fr
Abstract
In that paper we talk about triangle-free simple graphs with given maximum average
degree less than 22/9. We give an upper bound for the circular chromatic number
of such graphs which is at most 11/4. We give two other results whose proofs are
omitted. We use a discharging method with forbidden configurations. We also omit
in this paper the proof that they are indeed forbidden. These proofs rely on a recent
paper [4] of Raspaud and Zhu and are all straight-forward.
1
Partially supported by EGIDE, programme Lavoisier
Electronic Notes in Discrete Mathematics 28 (2007) 507–514
1571-0653/$ – see front matter © 2007 Elsevier B.V. All rights reserved.
www.elsevier.com/locate/endm
doi:10.1016/j.endm.2007.01.078