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Concept# Jean Leray

Summary

Jean Leray (ləʁɛ; 7 November 1906 – 10 November 1998) was a French mathematician, who worked on both partial differential equations and algebraic topology.
He was born in Chantenay-sur-Loire (today part of Nantes). He studied at École Normale Supérieure from 1926 to 1929. He received his Ph.D. in 1933. In 1934 Leray published an important paper that founded the study of weak solutions of the Navier–Stokes equations. In the same year, he and Juliusz Schauder discovered a topological invariant, now called the Leray–Schauder degree, which they applied to prove the existence of solutions for partial differential equations lacking uniqueness.
From 1938 to 1939 he was professor at the University of Nancy. He did not join the Bourbaki group, although he was close with its founders.
His main work in topology was carried out while he was in a prisoner of war camp in Edelbach, Austria from 1940 to 1945. He concealed his expertise on differential equations, fearing that its connections with applied mathematics could lead him to be asked to do war work.
Leray's work of this period proved seminal to the development of spectral sequences and sheaves. These were subsequently developed by many others, each separately becoming an important tool in homological algebra.
He returned to work on partial differential equations from about 1950.
He was professor at the University of Paris from 1945 to 1947, and then at the Collège de France until 1978.
He was awarded the Malaxa Prize (Romania, 1938), the Grand Prix in mathematical sciences (French Academy of Sciences, 1940), the Feltrinelli Prize (Accademia dei Lincei, 1971), the Wolf Prize in Mathematics (Israel, 1979), and the Lomonosov Gold Medal (Moscow, 1988). He was an elected to the American Academy of Arts and Sciences and the American Philosophical Society in 1959 and the United States National Academy of Sciences in 1965.

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Related concepts (9)

Related publications (2)

Sheaf (mathematics)

In mathematics, a sheaf (: sheaves) is a tool for systematically tracking data (such as sets, abelian groups, rings) attached to the open sets of a topological space and defined locally with regard to them. For example, for each open set, the data could be the ring of continuous functions defined on that open set. Such data is well behaved in that it can be restricted to smaller open sets, and also the data assigned to an open set is equivalent to all collections of compatible data assigned to collections of smaller open sets covering the original open set (intuitively, every piece of data is the sum of its parts).

Sheaf cohomology

In mathematics, sheaf cohomology is the application of homological algebra to analyze the global sections of a sheaf on a topological space. Broadly speaking, sheaf cohomology describes the obstructions to solving a geometric problem globally when it can be solved locally. The central work for the study of sheaf cohomology is Grothendieck's 1957 Tôhoku paper. Sheaves, sheaf cohomology, and spectral sequences were introduced by Jean Leray at the prisoner-of-war camp Oflag XVII-A in Austria.

Spectral sequence

In homological algebra and algebraic topology, a spectral sequence is a means of computing homology groups by taking successive approximations. Spectral sequences are a generalization of exact sequences, and since their introduction by , they have become important computational tools, particularly in algebraic topology, algebraic geometry and homological algebra. Motivated by problems in algebraic topology, Jean Leray introduced the notion of a sheaf and found himself faced with the problem of computing sheaf cohomology.

Rapport d’expertise sur l’analyse de la propagation des fumées durant l’accident du 24/10/2001 dans le tunnel du Gotthard. Expertise destinée au Procureur public du canton du Tessin

2002A proof of existence is given for a stationary model of alloy solidification. The system is composed of heat equation, solute equation and Navier-Stokes equations. In rite latter Carman-Kozeny penalization of porous medium models the mushy zone. The proble ...

1995