Ellen Gethner, Bopanna Kallichanda, Alexander S. Mentis,
Sarah Braudrick, Sumeet Chawla, Andrew Clune, Rachel
Drummond, Panagiota Evans, William Roche and Nao Takano
We continue the investigation of A. B. Kempe’s flawed proof of the Four Color
Theorem from a computational and historical point of view. Kempe’s “proof” gives
rise to an algorithmic method of coloring plane graphs that sometimes yields a proper
vertex coloring requiring four or fewer colors. We investigate a recursive version of
Kempe’s method and a modified version based on the work of I. Kittell. Then we
empirically analyze the performance of the implementations on a variety of
historically motivated benchmark graphs and explore the usefulness of simple
randomization in four-coloring small plane graphs. We end with a list of open
questions and future work.