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3-coloring triangle-free planar graphs with a precolored 8-cycle (1305.2467v1)
Published 11 May 2013 in math.CO and cs.DM
Abstract: Let G be a planar triangle-free graph and let C be a cycle in G of length at most 8. We characterize all situations where a 3-coloring of C does not extend to a proper 3-coloring of the whole graph.