Dehn značenje | engleski leksikon

(1878-1952)
German-born US mathematician who in 1907 provided one of the first systematic studies of topology. His work was mainly concerned with the geometric properties of polyhedrons.
Dehn was born in Hamburg and studied at Göttingen University under David Hilbert. After World War I Dehn became professor of mathematics at Frankfurt University, but lost his position 1935 because of the Nazi anti-Semitism laws. He immigrated 1940 to the US, and worked from 1945 at the Black Mountain College in North Carolina.
Dehn found a solution to one of Hilbert's 23 unsolved problems (concerning the existence of tetrahedrons with equal bases and heights, but not equal in the sense of division and completeness).
In 1910, Dehn proved an important theorem on topological manifolds. The theorem came to be known as Dehn's lemma, but was later found not to apply in all circumstances. Dehn continued to work on topological problems of transformation and isomorphism.