On the chromatic number of the general Kneser-graph

Circular chromatic numbers of some reduc

Circular chromatic numbers of some reduced Kneser graphs

✍ Ko-Wei Lih; Daphne Der-Fen Liu 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 75 KB

## Abstract The vertex set of the reduced Kneser graph KG~2~(__m,2__) consists of all pairs {__a,b__} such that __a, b__ε{1,2,…,__m__} and 2≤|__a__−__b__|≤__m__−2. Two vertices are defined to be adjacent if they are disjoint. We prove that, if __m__≥4 __and m__≠5, then the circular chromatic number

On the chromatic number of disk graphs

✍ Malesi?ska, Ewa; Piskorz, Steffen; Wei�enfels, Gerhard 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 172 KB 👁 2 views

Colorings of disk graphs arise in the study of the frequency-assignment problem in broadcast networks. Motivated by the observations that the chromatic number of graphs modeling real networks hardly exceeds their clique number, we examine the related properties of the unit disk (UD) graphs and their

On the chromatic number of the product o

On the chromatic number of the product of graphs

✍ D. Duffus; B. Sands; R. E. Woodrow 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 English ⚖ 429 KB 👁 1 views

The star chromatic number of a graph

✍ H. L. Abbott; B. Zhou 📂 Article 📅 1993 🏛 John Wiley and Sons 🌐 English ⚖ 469 KB 👁 2 views

## Abstract We study a generalization of the notion of the chromatic number of a graph in which the colors assigned to adjacent vertices are required to be, in a certain sense, far apart. © 1993 John Wiley & Sons, Inc.

The chromatic covering number of a graph

✍ Reza Naserasr; Claude Tardif 📂 Article 📅 2006 🏛 John Wiley and Sons 🌐 English ⚖ 72 KB 👁 2 views

Following [1] , we investigate the problem of covering a graph G with induced subgraphs G 1 ; . . . ; G k of possibly smaller chromatic number, but such that for every vertex u of G, the sum of reciprocals of the chromatic numbers of the G i 's containing u is at least 1. The existence of such ''ch

The chromatic number of oriented graphs

✍ Sopena, Eric 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 198 KB 👁 2 views

We introduce in this paper the notion of the chromatic number of an oriented graph G (that is of an antisymmetric directed graph) defined as the minimum order of an oriented graph H such that G admits a homomorphism to H. We study the chromatic number of oriented k-trees and of oriented graphs with