Title
The signed chromatic number of the projective plane and Klein bottle and antipodal graph coloring
Abstract
A graph with signed edges (a signed graph ) is k-colorable if its vertices can be colored using only the colors 0, ±1, ..., ± k so that the colors of the endpoints of a positive edge are unequal while those of a negative edge are not negatives of each other. Consider the signed graphs without positive loops that embed in the Klein bottle so that a closed walk preserves orientation iff its sign product is positive. All of them are 2-colorable but not all are 1-colorable, not even if one restricts to the signed graphs that embed in the projective plane. If the color 0 is excluded, all are 3-colorable but, even restricting to the projective plane, not necessarily 2-colorable.
Year
DOI
Venue
1995
10.1006/jctb.1995.1009
J. Comb. Theory, Ser. B
Keywords
Field
DocType
klein bottle,chromatic number,antipodal graph coloring,projective plane,graph coloring
Real projective plane,Discrete mathematics,Edge coloring,Combinatorics,Signed graph,Fractional coloring,Projective plane,Mathematics,Planar graph,Graph coloring,Complement graph
Journal
Volume
Issue
ISSN
63
1
Journal of Combinatorial Theory, Series B
Citations 
PageRank 
References 
0
0.34
0
Authors
1
Name
Order
Citations
PageRank
T. Zaslavsky129756.67