Gerhard Ringel

Gerhard Ringel (28 October 1919 in Kollnbrunn, Austria to 24 June 2008 in Santa Cruz, California) was a German mathematician and one of the pioneers in graph theory. He contributed significantly to the proof of the Heawood conjecture, now the Ringel-Youngs theorem, a problem closely linked with the four color theorem. Although born in Austria, he was raised in Czechoslovakia and attended Charles University before being drafted into the Wehrmacht in 1940, and after the war he served for over four years in a Soviet prisoner of war camp. He earned his doctorate at the University of Bonn in 1951 under Emanuel Sperner and Ernst Peschl, began his academic career as a professor at the Free University Berlin, and in 1970 left Germany for the University of California, Santa Cruz.