Person: Appel, Kenneth Ira
Kenneth Appel was an American mathematician bestknown for his part in proving the fourcolour theorem.
Mathematical Profile (Excerpt):
 Irwin Appel was born in Russia but emigrated to the United States.
 Appel was educated in New York.
 After graduating, Appel spent a short spell working as an actuary before serving for two years in the US army.
 After two years of army service, Appel enrolled in the graduate programme at the University of Michigan in 1955.
 Another important event in Appel's life happened while he was a graduate student.
 Appel worked at this Center in Princeton using both his mathematical and computing expertise.
 Following his two years with the Institute for Defense Analyses in Princeton, Appel was offered a assistant professorship at the University of Illinois at Urbana.
 This result using computers to prove a mathematical theorem, was a technique that Appel used to great effect as we explain below.
 Appel is best known, however, for his work with his colleague at the University of Illinois at Urbana, Wolfgang Haken where again he used computers to prove a theorem.
 Appel and Haken published their first step towards a proof with The existence of unavoidable sets of geographically good configurations in 1976.
 What makes the claim of Appel and Haken more convincing?
 The proof was published in 1989 by Appel and Haken in the form of a book with title Every planar map is four colorable.
 For their remarkable achievement, Appel and Haken were awarded the Delbert Ray Fulkerson prize by the American Mathematical Society and the Mathematical Programming Society in 1979.
 In 1993 Appel left the University of Illinois and moved to New Hampshire when he was appointed as the Chairman of the Mathematics Department at the University of New Hampshire.
 Retirement did not end Appel's involvement with teaching mathematics, however, for he was keen to participate in mathematics enrichment programmes in Dover schools and other southern Maine schools.
 Appel's hobbies included playing tennis, collecting stamps, playing Go, and baking bread.
 In October 2012 Appel was diagnosed with esophageal cancer.
Born 8 October 1932, Brooklyn, New York, USA. Died 19 April 2013, Dover, New Hampshire, USA.
View full biography at MacTutor
Tags relevant for this person:
Origin Usa, Puzzles And Problems, Topology
Thank you to the contributors under CC BYSA 4.0!
 Github:

 nonGithub:
 @JJO'Connor
 @EFRobertson
References
Adapted from other CC BYSA 4.0 Sources:
 Oâ€™Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive