Pavel Samuilovich Urysohn
Pawel Samuilowitsch Urysohn, Russian Павел Самуилович Урысон, German and Paul Urysohn (born 22 Januarjul / February 3 1898greg in Odessa, Ukraine today, .. † August 17, 1924 in Batz -sur -Mer, France) was a Russian mathematician, which was mainly concerned with set-theoretic topology.
Life and work
He studied from 1915 at the Lomonosov Moscow State University with Nikolai Luzin and Dmitri Fyodorovich Egorov mathematics, after he started with physics and also in the first year published a physical attachment. In 1919 he received his diploma and his habilitation in 1921 with a thesis on integral equations, after which he had a lectureship at the University of Moscow. An important class of nonlinear integral equations now bears his name.
Inspired by some questions Yegorov, he dealt with the concept of dimension in the set-theoretic topology, without knowing the work of the famous topologist Brouwer ( 1913). He developed the theory he published in the archives of the French Academy ( Comptes rendus ) in 1922 and in the Polish " Fundamenta Mathematica ". Later, his friend Pavel Alexandrov, with whom he visited Göttingen 1923-1924, the equivalence to the theory of Karl Menger recognized. On her last trip to Western Europe in 1924 he visited Alexandrov and David Hilbert in Göttingen, Felix Hausdorff in Bonn and Brouwer in Amsterdam. Thereafter, the two rented a cottage in Brittany, where Urysohn drowned at one of their swimming trips in the Atlantic in rough seas. He had swum out on a Sunday with Alexandrov, 17 against clock and both wanted to because of the strong swell, turn back. Alexandroff made it to shore, still took the lifeless driving Urysohn on a rope that a local resident had thrown him, backed out of the sea, the resuscitation attempts were unsuccessful, however. He is buried in Batz -sur -Mer. Alexandrov gave up the last work of his friend. Urysohn had last worked on the theory of metric spaces, where some fundamental results of which it is affiliated. In the work to Metrisationsproblem he had worked all day at his death, before he went for a swim.