‎"LERAY, JEAN. - A TURNING POINT IN TOPOLOGY.‎
‎L'anneau d'homologie d'une représentation. (+) Structure de l'anneau d'homologie d'une représentation. (2 papers).‎

‎(Paris, Gauthier-Villars), 1946). 4to. No wrappers. In: ""Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences"", Tome 222, No 24 a. 25. Pp. (1361-) 1416 a. pp. (1417-) 1464. (2 entire issues offered). Leray's papers: pp. 1366-1368 a. pp. 1419-1422.‎

Reference : 49676

‎First printing of these two landmark papers in topology. Dieudonné later wrote ""undoubtly rank (the papers) at the same level in the history of mathematics as the methods invented by Poincaré and Brouwer"".""These two Comptes Rendus notes of Leray from 1946 introduced the novel concepts of sheafs, sheaf cohomology, and spectral sequences, which he had developed during his years of captivity as a prisoner of war. Leray's announcements and applications (published in other Comptes Rendus notes from 1946) drew immediate attention from other mathematicians. Subsequent clarification, development, and generalization by Henri Cartan, Jean-Louis Koszul, Armand Borel, Jean-Pierre Serre, and Leray himself allowed these concepts to be understood and applied to many other areas of mathematics....."" (List of importent publications in mathematics).‎