Vem daterade Pavel Urysohn?

Pavel Samuilovich Urysohn (in Russian: Па́вел Самуи́лович Урысо́н; 3 February 1898 – 17 August 1924) was a Soviet mathematician who is best known for his contributions to the theory of topological dimension, and for developing Urysohn's metrization theorem and Urysohn's lemma, both of which are fundamental results in topology. He also constructed what is now called the Urysohn universal space and his name is also commemorated in the terms Fréchet–Urysohn space, Menger–Urysohn dimension and Urysohn integral equation. He and Pavel Alexandrov formulated the modern definition of compactness in 1923.

Pavel Sergejevitj Aleksandrov, född 7 maj 1892, död 16 november 1982, var en sovjetisk matematiker.

Aleksandrov gjorde fundamentala upptäckter, bland annat inom dimensions- och homologiteorin och var en av grundarna av den sovjetiska skolan inom topologin