Charles Ehresmann

Charles Ehresmann
Charles Ehresmann (right) at the topology conference 1949 in Oberwolfach, together with Paul Vincensini (middle) and Georges Reeb (left)
Born	19 April 1905(1905-04-19) Straßburg, Alsace-Lorraine, German Empire (today Strasbourg, Alsace, France)
Died	22 September 1979(1979-09-22) (aged 74) Amiens, Picardy, France
Fields	Mathematics
Alma mater	École Normale Supérieure
Doctoral advisor	Élie Cartan
Doctoral students	Georges Reeb Wu Wen-Tsün André Haefliger Valentin Poénaru Daniel Tanré
Known for	Ehresmann's theorem Ehresmann connection

Charles Ehresmann (19 April 1905 – 22 September 1979) was a French mathematician who worked on differential topology and category theory. He is known for work on the topology of Lie groups, the jet concept (see jet bundle), and his seminar on category theory.

He attended the École Normale Supérieure in Paris before performing one year of military service. He finished his PhD thesis Sur la topologie de certains espaces homogènes (French: On the topology of certain homogeneous spaces) in 1934 under the supervision of Élie Cartan.

In 1957 he founded the mathematical journal Cahiers de Topologie et Géometrie Différentielle Categoriques.

Jean Dieudonné describes Ehresmann's personality as "... distinguished by forthrightness, simplicity, and total absence of conceit or careerism. As a teacher he was outstanding, not so much for the brilliance of his lectures as for the inspiration and tireless guidance he generously gave to his research students ... "

He had 76 Ph.D. students, including Georges Reeb, Wu Wen-Tsün, André Haefliger, Valentin Poénaru, Daniel Tanré.

See also

• Ehresmann's theorem
• Ehresmann connection

References

• International Conference "Charles Ehresmann : 100 ans", Université de Picardie Jules Verne à Amiens, 7-8-9 October 2005, http://pagesperso-orange.fr/vbm-ehr/ChEh/indexAng.htm
• `The mathematical legacy of Charles Ehresmann', Proceedings of the 7th Conference on the Geometry and Topology of Manifolds: The Mathematical Legacy of Charles Ehresmann, Bedlewo (Poland) 8.05.2005-15.05.2005, Edited by J. Krysinski, J. Pradines, T. Rybicki, R. Wolak, Banach Centre Publications 76, Institute of Mathematics Polish Academy of Sciences, Warsaw, (2007).

External links

• O'Connor, John J.; Robertson, Edmund F., "Charles Ehresmann", MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Ehresmann.html .
• Charles Ehresmann at the Mathematics Genealogy Project.

Persondata
Name	Ehresmann, Charles
Alternative names
Short description
Date of birth	19 April 1905
Place of birth	Straßburg, Alsace-Lorraine, German Empire (today Strasbourg, Alsace, France)
Date of death	22 September 1979
Place of death	Amiens, Picardy, France