Person: Appel, Kenneth Ira
Kenneth Appel was an American mathematician best-known for his part in proving the four-colour 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 BY-SA 4.0! 
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- non-Github:
- @J-J-O'Connor
- @E-F-Robertson
References
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive
