Colored Homomorphisms of Colored Mixed Graphs
نویسندگان
چکیده
The homomorphisms of oriented or undirected graphs, the oriented chromatic number, the relationship between acyclic coloring number and oriented chromatic number, have been recently studied. Improving and combining earlier techniques of N. Alon and T. H. Marshall (1998, J. Algebraic Combin. 8, 5 13) and A. Raspaud and E. Sopena (1994, Inform. Process. Lett. 51, 171 174) we prove here a general result about homomorphisms of colored mixed graphs which implies all these earlier results about planar graphs. We also determine the exact chromatic number of colored mixed trees. For this, we introduce the notion of colored homomorphism for mixed graphs containing both colored arcs and colored edges. 2000 Academic Press
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ورودعنوان ژورنال:
- J. Comb. Theory, Ser. B
دوره 80 شماره
صفحات -
تاریخ انتشار 2000