Ehresmann

Ehresmann is a French surname that is most widely recognized because of Charles Ehresmann, a prominent mathematician who made foundational contributions to differential geometry and topology in the twentieth century. Born in Bavel, Belgium in 1901, Ehresmann studied at the Université libre de Bruxelles and later at the École normale supérieure in Paris. He earned his Ph.D. in 1928 and subsequently held academic positions at institutions including the University of Lille and the University of Paris. Ehresmann's research focused on the theory of fiber bundles, Lie groups, and connections on manifolds, laying groundwork that has influenced both mathematics and theoretical physics.

Among his most noted achievements is the formalization of the Ehresmann connection, a generalization of the notion of parallel transport that applies to arbitrary fiber bundles. He also introduced the concept of the Ehresmann submersion and contributed to the study of holonomy, as well as the classification of differential structures on manifolds. The term “Ehresmann fibration” is now a standard adjective in the literature of differential topology. In addition to his research, Ehresmann authored several influential monographs, including “Fibrés Différentiels” (1968) and “Catégories Différentielles” (1970). He was a member of the French Academy of Sciences and received numerous honors, including the Grand Cross of the Légion d'honneur. Ehresmann retired in the late 1960s and died in 1994. His legacy endures through the many mathematical concepts that bear his name and continue to be central in modern geometry and related fields.