Person: Leray, Jean
Jean Leray was a French mathematician who worked on algebraic topology and differential equations.
Mathematical Profile (Excerpt):
 Jean attended the Lycée at Nantes, then moving to the Lycée at Rennes before completing his education at the École Normale Supérieure where he was awarded his doctorate.
 This led to a collaboration between Leray and Schauder and their joint work led to a paper Topologie et équations fonctionelles Ⓣ(Topology and functional equations) published in the Annales scientifiques de l'École normale Supérieure.
 After his 1934 paper with Schauder, Leray published a paper on algebraic topology in the following year on the topology of Banach spaces.
 In producing this theory Leray introduced many ideas of functional analysis which have today become standard tools.
 In 1936 Leray was appointed Professor at the Faculty of Science at Nancy.
 While at the camp Leray and some of his fellow captives organised a "université en captivité" and Leray became its rector.
 Not wishing the Germans to know that he was an expert in hydrodynamics, since he feared that if they found out he would be forced to undertake war work for them, Leray claimed to be a topologist.
 Although he had undertaken some topological work it was not easy for Leray to work on the topic without reading topological literature.
 He was able to obtain some papers through Hopf who was at this time in Zürich but much of Leray's work was done independently of the developments which had taken place in the subject.
 After his release in 1945 Leray published a three part work Algebraic topology taught in captivity.
 Leray continued to work on topological questions after his return to Paris where he became professor at the Collège de France in 1947.
 In the 1950s Leray worked in a number of areas.
 Leray's work on the Cauchy problem led him to study residues theory.
 Leray received many honours.
Born 7 November 1906, Chantenay, near Nantes, LoireInférieure, France. Died 10 November 1998, La Baule, LoireAtlantique, France.
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Tags relevant for this person:
Bourbaki, Topology, Prize Wolf
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 @JJO'Connor
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References
Adapted from other CC BYSA 4.0 Sources:
 O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive