Thirteen colorful variations on Guthrie
Joseph M. Katz Graduate School of Business
University of Pittsburgh
: Jan, 1972
: The American Mathematical MonthlyVol.: 79- Issue: 1- Pages: 2-43
: After careful analysis of information regarding the origins of the four-color conjecture, Kenneth O. May concludes that: It was not the culmination of a series of individual efforts that flashes across the mind of Francis Guthrie while coloring a map of England... his brother communicated the conjecture, but not the attempted proof to De Morgan in October 1852.
: Four color problem, Graph theory