Jacques Feldbau was a French mathematician, born on 22 October in Strasbourg , of an Alsatian Jewish traditionalist family. As a mathematician he worked on differential geometry and topology. He was the first student of Charles Ehresmann. He is known as one of the founders of the theory of fiber bundles.
He is the one who first proved that a fiber bundle over a simplex is trivializable and who used this to classify bundles over spheres. In a paper, written together with Ehresmann, he introduced the notion of an associated bundle and proved results known today as the exact homotopy sequence of a fibration.
He enrolled at the University of Strasbourg in , where he was librarian of the Institute of Mathematics in He was also a pianist and swimmer. As soon as the s, Feldbau was participating in a "defence group against anti-Semitism.
Mobilized in , he became a flying officer in the French Air Force. He then went to Clermont-Ferrand, where the University of Strasbourg had been evacuated to, where he met his supervisor, Charles Ehresmann. In order to earn a living he gave mathematics lessons and continued his research in topology for his doctoral thesis; he also became a member of the Resistance movement. The status of Jews was one of the additional burdens of Nazi occupation; it quickly became impossible for a scientist labelled as "non- Aryan " to publish under his name.
It was eventually published under the sole name of Ehresmann albeit with mention of the results being obtained "in collaboration with one of his students". The name "Feldbau" in German means "agriculture". Closer to the war, a very gifted student, Jacques Feldbau, asked me to suggest a topic in topology. I consulted Ehresmann, who was far better versed in the field than I.
