## Abstract We show that every plane graph with maximum face size four in which all faces of size four are vertex‐disjoint is cyclically 5‐colorable. This answers a question of Albertson whether graphs drawn in the plane with all crossings independent are 5‐colorable. © 2009 Wiley Periodicals, Inc.
On graphs with strongly independent color-classes
✍ Scribed by A. Gyárfás; T. Jensen; M. Stiebitz
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 148 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
We prove that for every k there is a k‐chromatic graph with a k‐coloring where the neighbors of each color‐class form an independent set. This answers a question raised by N. J. A. Harvey and U. S. R. Murty [4]. In fact we find the smallest graph G~k~ with the required property for every k. The graph G~k~ exhibits remarkable similarity to Kneser graphs. The proof that G~k~ is k‐chromatic relies on Lovász's theorem about the chromatic number of graphs with highly connected neighborhood complexes. © 2004 Wiley Periodicals, Inc. J Graph Theory 46: 1–14, 2004
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