A (k, 1)-coloring of a graph is a vertex-coloring with k colors such that each vertex is permitted at most 1 neighbor of the same color. We show that every planar graph has at least c n distinct (4, 1)-colorings, where c is constant and β 1.466 satisfies 3 = 2 +1. On the other hand for any >0, we gi
A note on defective colorings of graphs in surfaces
β Scribed by Dan Archdeacon
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 139 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
A graph is (rn, k)-colorable if its vertices can be colored with rn colors in such a way that each vertex is adjacent to at most k vertices of the same color as itself. In a recent paper Cowen. Cowen, and Woodall proved that, for each compact surface S, there exists an integer k = k(S) such that every graph in S can be (4, k)-colored. They also conjectured that the 4 could be replaced by 3. In this note we prove their conjecture.
π SIMILAR VOLUMES
## Abstract The distance coloring number __X__~__d__~(__G__) of a graph __G__ is the minimum number __n__ such that every vertex of __G__ can be assigned a natural number __m__ β€ __n__ and no two vertices at distance __i__ are both assigned __i__. It is proved that for any natural number __n__ ther
It can easily be seen that a conjecture of RUNGE does not hold for a class of graphs whose members will be called "almost regular". This conjecture is replaced by a weaker one, and a classification of almost regular graphs is given.