It is proved that if G is a planar graph with total (vertex-edge) chromatic number Ο , maximum degree and girth g, then Ο = + 1 if β₯ 5 and g β₯ 5, or β₯ 4 and g β₯ 6, or β₯ 3 and g β₯ 10. These results hold also for graphs in the projective plane, torus and Klein bottle.
List colourings of planar graphs
β Scribed by Margit Voigt
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 259 KB
- Volume
- 120
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
A graph G = G( V, E) is called L-list colourable if there is a vertex colouring of G in which the colour assigned to a vertex u is chosen from a list L(v) associated with this vertex. We say G is k-choosable if all lists L(u) have the cardinality k and G is L-list colourable for all possible assignments of such lists. There are two classical conjectures from Erd&, Rubin and Taylor 1979 about the choosability of planar graphs:
(1) every planar graph is 5-choosable and, (2) there are planar graphs which are not 4-choosable.
We will prove the second conjecture.
π SIMILAR VOLUMES
## Abstract Given an edge coloring __F__ of a graph __G__, a vertex coloring of __G__ is __adapted to F__ if no color appears at the same time on an edge and on its two endpoints. If for some integer __k__, a graph __G__ is such that given any list assignment __L__ to the vertices of __G__, with |_
## Abstract The acyclic list chromatic number of every planar graph is proved to be at most 7. Β© 2002 Wiley Periodicals, Inc. J Graph Theory 40: 83β90, 2002
This paper exploits the remarkable new method of Galvin (J. Combin. Theory Ser. B 63 (1995), 153 158), who proved that the list edge chromatic number /$ list (G) of a bipartite multigraph G equals its edge chromatic number /$(G). It is now proved here that if every edge e=uw of a bipartite multigrap
We prove that every planar graph of girth at least 5 is 3-choosable. It is even possible to precolor any 5-cycle in the graph. This extension implies GrΓΆtzsch's theorem that every planar graph of girth at least 4 is 3-colorable. If 1995 Academic Press, Inc.