Heawood graph
Sign in to saveundirected graph with 14 vertices, 21 edges, and girth 6
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Heawood graph
jaanos.github.io →Percy John Heawood (1861-1955) was an English mathematician who spent a large amount of time on questions related to the four colour theorem. Heawood proved the 7-color theorem for the torus. This graph has an embedding on the torus with 7 areas that are mutually adjacent, showing that 7 is best possible.
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