Charles Ehresmann

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 worked on differential topology and category theory.

Life

Honor 's father was a gardener and he came from an Alsatian -speaking family. He attended school in Strasbourg and the École Normale Supérieure from 1924 (ENS ) in Paris. After graduating in 1927 he did his military service and then taught from 1928 to 1929 at a French high school in Rabat in Morocco. 1930/31 he studied in Göttingen and from 1932 to 1934 in Princeton. In 1934 he was in Paris his doctorate at the ENS in Elie Cartan with the thesis Sur la topology de certains espaces homogeneous and then was a researcher at the CNRS. He examined the homology of different multiplicities as those of the classical groups, homogeneous spaces and Grassmann manifolds. 1935 to 1937 he was active in the seminar by Gaston Julia, the forerunner of the Bourbaki seminars. In 1939 he was a lecturer in Strasbourg, more with the other faculty members of the German occupation in 1940 to Clermont- Ferrand, where the French University of Strasbourg had been outsourced. After the German retreat from France, a man of honor in 1945 returned back to Strasbourg. In 1955 he became professor of topology in Paris, first at the Sorbonne and after the start-up Parisian universities in 1969 at the University of Paris VII Denis Diderot. In 1975, he retired. In retirement, he was still to 1978 lectures in Amiens ( Université de Picardie ), where he moved, as his second wife Andrée Charles Ehresmann was a professor of mathematics there. He also had guest professorships, among others, in Yale, Princeton, Brazil (São Paulo, Rio de Janeiro), Buenos Aires, Mexico, Montreal and at the Tata Institute in Bombay.

Gentleman was a pioneer in differential topology, where he developed the concept of fiber space building on the work of Herbert Seifert and Hassler Whitney developed ( in parallel with Norman Steenrod in the U.S.). From 1957 he played a leading role in the development of category theory.

His collected works were published from 1980 to 1983 in seven volumes ( 4 volumes at the Imprimerie Evrard, Amiens, supplements in the Cahiers de topology et de Géométrie différentielle founded by him ), edited by his wife. Among his doctoral students (over 70 ) include Georges Reeb, Wu Wenjun, André Haefliger, Paulette Libermann, Jacques field crops and Valentin Poenaru.

In 1965 his book Catégories et structures at Dunod in Paris, in 1969 his Algèbre.

He holds honorary doctorates from the University of Bologna.