zbMATH — the first resource for mathematics

An oriented 7-colouring of planar graphs with girth at least 7. (Russian. English summary) Zbl 1095.05013
Summary: An oriented $$k$$-colouring of digraph $$H$$ is an oriented homomorphism of $$H$$ into a $$k$$-vertex tournament. We prove that every orientation of a plane graph with girth at least 7 has an oriented 7-colouring.

MSC:
 05C15 Coloring of graphs and hypergraphs
Full Text: