Charles Ehresmann

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Charles Ehresmann (born April 19, 1905 in Strasbourg , † September 22, 1979 in Amiens ) was a French mathematician who was one of the founders of Bourbaki . He dealt with differential topology and category theory .

Charles Ehresmann (right) at the 1949 Topology Conference in Oberwolfach , together with Paul Vincensini (center) and Georges Reeb (left).

Life

Ehresmann's father was a gardener and he came from an Alsatian- speaking family. He attended school in Strasbourg and from 1924 the École normal supérieure (ENS) in Paris . After graduating in 1927, he did military service and then taught at a French high school in Rabat in Morocco from 1928 to 1929 . In 1930/31 he studied in Göttingen and from 1932 to 1934 in Princeton . In 1934 he received his doctorate in Paris at the ENS with Élie Cartan with the dissertation Sur la topologie de certains espaces homogènes and was then a researcher at the CNRS . He investigated the homology of various manifolds such as that of classical groups, homogeneous spaces, and Graßmann manifolds. From 1935 to 1937 he was active in Gaston Julia's seminar , the forerunner of the Bourbaki seminars. In 1939 he was a lecturer in Strasbourg, and with the other faculty members during the German occupation in 1940 he moved to Clermont-Ferrand , where the French University of Strasbourg had been relocated. After the German withdrawal from France, Ehresmann returned to Strasbourg in 1945. In 1955 he became professor of topology in Paris, first at the Sorbonne and after the founding of Paris universities in 1969 at the University of Paris VII Denis Diderot. In 1975 he retired. In retirement he gave lectures in Amiens (Université de Picardie) until 1978 , where he moved because his second wife Andrée Charles-Ehresmann was professor of mathematics there. He was also visiting professor at Yale , Princeton , Brazil (São Paulo, Rio de Janeiro), Buenos Aires, Mexico, Montreal and at the Tata Institute in Bombay.

Ehresmann was a pioneer in differential topology , where he developed the concept of fiber spaces based on the work of Herbert Seifert and Hassler Whitney (parallel to Norman Steenrod in the USA). From 1957 he was a leader in the development of category theory.

His collected works appeared in seven volumes from 1980 to 1983 (four volumes at the Imprimerie Evrard, Amiens, supplements in the Cahiers de topologie et de Géométrie différentielle , which he founded ), edited by his wife. His doctoral students (over 70) include Georges Reeb , Wu Wenjun , André Haefliger , Paulette Libermann , Jacques Feldbau and Valentin Poénaru .

In 1965 his book Catégories et structures was published by Dunod in Paris, in 1969 his Algèbre .

He is an honorary doctor from the University of Bologna . In 1965 he was president of the Société Mathématique de France .

See also

Web links

personal data
SURNAME Ehresmann, Charles
BRIEF DESCRIPTION French mathematician
DATE OF BIRTH April 19, 1905
PLACE OF BIRTH Strasbourg
DATE OF DEATH 22nd September 1979
Place of death Amiens