E16. Olde Victorian Map Colouring
Let us start with the history of the arguably second most famous problem in the entire history of mathematics. It commences in Victorian London in the year 1852, when the 20-year old Francis Guthrie created The Four-Color Conjecture (4CC), and continues for 124 years, when in 1976 Kenneth Appel and Wolfgang Haken, with the assistance of John Koch and over 1200 hour of mainframe computer time converted 4CC into 4CT – The Four Color Theorem. A second proof had to wait another 20 years: in 1997 Neil Robertson, Daniel Sanders, Paul Seymour and Robin Thomas also proved 4CT. Both proofs required an essential use of computing.
KeywordsChromatic Number Dual Graph Common Boundary Edge Coloring Entire History
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