On October 23, 1852, Professor Augustus De Morgan wrote a letter to a colleague, unaware that he used to be launching essentially the most well-known mathematical conundrums in history--one that might confound hundreds of thousands of puzzlers for greater than a century. this can be the fantastic tale of the way the "map challenge" used to be solved.
The challenge posed within the letter got here from a former pupil: what's the least attainable variety of colours had to fill in any map (real or invented) in order that neighboring counties are constantly coloured another way? This deceptively basic query was once of minimum curiosity to cartographers, who observed no use to restrict what percentage shades they used. however the challenge trigger a frenzy between expert mathematicians and beginner challenge solvers, between them Lewis Carroll, an astronomer, a botanist, an obsessive golfer, the Bishop of London, a guy who set his watch just once a yr, a California site visitors cop, and a bridegroom who spent his honeymoon coloring maps. of their pursuit of the answer, mathematicians painted maps on doughnuts and horseshoes and performed with patterned football balls and the good rhombicuboctahedron.
it'd be multiple hundred years (and numerous coloured maps) later sooner than the end result used to be eventually demonstrated. Even then, tough questions remained, and the complex solution--which concerned no fewer than 1,200 hours of laptop time--was greeted with as a lot dismay as enthusiasm.
Providing a transparent and stylish rationalization of the matter and the evidence, Robin Wilson tells how a likely harmless query baffled nice minds and prompted intriguing arithmetic with far-flung functions. this is often the interesting tale of these who didn't end up, and people who finally did end up, that 4 colours do certainly suffice to paint any map.