Kenneth Appel, Ken Appel ( born October 8, 1932 in Brooklyn, New York City, † April 19, 2013 in Dover, New Hampshire ) was an American mathematician who primarily for his proof of the four color theorem with Wolfgang hook 1976 is known.
Appel studied until 1953 at Queens College ( bachelor's degree ), served two years in the U.S. Army and then continued his studies at the University of Michigan continues where Roger Lyndon with the dissertation Two Investigations on the borderline of Logic and he 1959 Algebra was awarded his doctorate.
He then worked for two years at the Institute for Defense Analyses in Princeton and then went in 1961 as an assistant professor at the University of Illinois at Urbana -Champaign, where he became in 1967 associate professor and in 1977 ordinary (full) professor and where he in 1976 together with Wolfgang hook proved the famous four- color theorem. This states that for any two-dimensional map ( with certain restrictions ) four colors are sufficient to color the map, without adjacent " countries" have the same color.
The proof came only through massive computer use and could only be verified by computer ( had to be checked approximately 1500 individual cases). He also marked evidence technically an incision in the history of mathematics - the beginning of what is now experimental mathematics is running under the collective term. In their evidence, they built on the ideas of Heinrich Heesch, who also worked in the 1960s at the Technical University of Hanover in a proof with the help of computers, but received insufficient financial support and was otherwise relatively isolated. Appel and Haken proof required for their 1200 hours of computing time on an IBM 360 with 64 kB of RAM that would otherwise only served administrative purposes at the University. Your work on the proof took about four years and began in 1972. Doing so, they were also supported by the children of Appel (his son Andrew is now also a professor of computer science at Princeton ). In celebration of the evidence, the University of Illinois introduced a new postmark Four colors suffice. Apparently most of the programming was carried out ( in assembly language ) by Appel, during the topologist hook contributed conceptual ideas.
Kenneth Appel was most recently a professor at the University of New Hampshire in Durham, where he was head of the Mathematics Department 1993-2002. He is a Fellow of the American Mathematical Society.
In 1979 he was awarded the Fulkerson Prize of the AMS for discrete mathematics with hooks.
He was married to Carole Stone since 1959.