منابع مشابه
Circular Chromatic Number and Graph Minors
This paper proves that for any integer n ≥ 4 and any rational number r, 2 ≤ r ≤ n − 2, there exists a graph G which has circular chromatic number r and which does not contain Kn as a minor.
متن کاملCircular Chromatic Ramsey Number
Let χc(H) denote the circular chromatic number of a graph H. For graphs F and G, the circular chromatic Ramsey number Rχc(F,G) is the infimum of χc(H) over graphs H such that every red/blue edge-coloring of H contains a red copy of F or a blue copy of G. We characterize Rχc(F,G) in terms of a Ramsey problem for the families of homomorphic images of F and G. Letting zk = 3 − 2 −k, we prove that ...
متن کاملThe Circular Chromatic Number of the Mycielski's Graph M
As a natural generalization of chromatic number of a graph, the circular chromatic number of graphs (or the star chromatic number) was introduced by A.Vince in 1988. Let M (G) denote the tth iterated Mycielski graph of G. It was conjectured by Chang, Huang and Zhu(Discrete mathematics,205(1999), 23-37) that for all n ≥ t+2, χc(M (Kn)) = χ(M (Kn)) = n+ t. In 2004, D.D.F. Liu proved the conjectur...
متن کاملMinors in Graphs with High Chromatic Number
THOMAS BÖHME, ALEXANDR KOSTOCHKA2† and ANDREW THOMASON 1Institut für Mathematik, Technische Universität Ilmenau, Ilmenau, Germany (e-mail: [email protected]) 2 Department of Mathematics, University of Illinois, Urbana, IL 61801, USA and Sobolev Institute of Mathematics, Novosibirsk, Russia (e-mail: [email protected]) 3 DPMMS, Centre for Mathematical Sciences, Wilberforce Road, ...
متن کاملCircular chromatic number: a survey
The circular chromatic number chi (c)(G) of a graph G (also known as 'the star-chromatic number'), is a natural generalization of the chromatic number of a graph. In this paper, we survey results on this topic, concentrating on the relations among the circular chromatic number, the chromatic number and some other parameters of a graph. Some of the results and or proofs presented here are new. T...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Taiwanese Journal of Mathematics
سال: 2000
ISSN: 1027-5487
DOI: 10.11650/twjm/1500407298