Walther von Dyck

Walther von Dyck made important contributions to function theory, group theory, where a fundamental result on group presentations is named after him, topology and potential theory. He was born in Munich on 6 December 1856 and died there on 5 November 1934. In 1882 he was the first to require inverse elements as part of the definition of a group, and in 1888 he proved the relation among surfaces now known as Dyck's theorem. His group-theory results and Dyck's theorem on surfaces carry his name.