Charles Ehresmann was a German-born French mathematician who worked in differential topology and category theory.
Charles Ehresmann (right) at the topology conference 1949 in Oberwolfach, together with Paul Vincensini (middle) and Georges Reeb (left)
Nicolas Bourbaki is the collective pseudonym of a group of mathematicians, predominantly French alumni of the École normale supérieure (ENS). Founded in 1934–1935, the Bourbaki group originally intended to prepare a new textbook in analysis. Over time the project became much more ambitious, growing into a large series of textbooks published under the Bourbaki name, meant to treat modern pure mathematics. The series is known collectively as the Éléments de mathématique, the group's central work. Topics treated in the series include set theory, abstract algebra, topology, analysis, Lie groups and Lie algebras.
Charles-Denis Bourbaki, 19th century general and namesake of the collective
Gaston Julia (right), who was not a member of Bourbaki, lost his nose during World War I. The war created a lost generation of mathematical knowledge, which the Bourbaki founders sought to fill.
Sign marking the official founding of Bourbaki in Besse-en-Chandesse
First book of the Éléments de mathématique, 1970 edition
