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Figure This!

In 1852 British student Frederick Guthrie asked whether any map drawn on a piece of paper can be colored with no more than four colors. Guthrie’s question became the “Four-Color Problem.”

The number of colors needed for a map drawn on other than flat surfaces was determined in 1968, eight years before the Four-Color Problem was solved.

In 1890, Heawood determined that it requires at most seven colors to color any map on a doughnut.

A. B. Kempe, a lawyer, published a proof of the Four-Color Problem in 1879, but P. J. Heawood found an error in Kempe’s proof in 1890. The problem remained unsolved until 1976 when mathematicians Kenneth Appel and Wolfgang Haken of the University of Illinois gave a proof based on more than 1000 hours of computer calculations.

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