Many 3-colorings of triangle-free planar graphs
Journal of Combinatorial Theory Series B
Note: Graphs with full rank 3-color matrix and few 3-colorings
Journal of Combinatorial Theory Series B
A step towards the strong version of Havel's three color conjecture
Journal of Combinatorial Theory Series B
Short proofs of coloring theorems on planar graphs
European Journal of Combinatorics
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If k is a prime power, and G is a graph withn vertices, then a k-coloring of G may beconsidered as a vector in GF(k)n.We prove that the subspace of GF(3)nspanned by all 3-colorings of a planar triangle-free graph withn vertices has dimension n. In particular, any suchgraph has at least n - 1 nonequivalent 3-colorings, and theaddition of any edge or any vertex of degree 3 results in a3-colorable graph. © 2000 John Wiley & Sons, Inc. J GraphTheory 34: 234245, 2000