Bojan Mohar, University of Ljubljana, Slovenia

Abstract :

The notion of the circular chromatic number is a natural refinement of the usual chromatic number. A generalization of this concept to graphs with edge-weights will be presented which naturally links the chromatic graph theory to several other, seemingly unrelated areas, e.g., the travelling salesman problem. An interesting special case is also a new notion of the chromatic number of a digraph whose main properties will be presented in some more depth.

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