Fritsch graph

From HandWiki

In the mathematical field of graph theory, the Fritsch graph is a planar graph with 9 vertices and 21 edges. It was obtained by Fritsch[1] as a minimal sized counterexample to the Alfred Kempe's attempt to prove the four-color theorem.

References

  1. Fritsch, Rudolf; Fritsch, Gerda (1998). The Four-Color Theorem. New York: Springer-Verlag. doi:10.1007/978-1-4612-1720-6.