**Eduard Stiefel** was a Swiss mathematician best known for his invention (with Hassler Whitney) of topological characteristic classes.

- perhaps Stiefel's most famous contribution to pure mathematics, was dedicated to a fundamental study of the theory of vector fields on manifolds.
- Following earlier work of H Cartan and H Weyl, he introduced the so-called Stiefel Diagram for continuous groups, relating closed semi-simple groups and discontinuous reflection groups.
- Stiefel was employed at ETH Zürich following the award of his doctorate.
- However he also undertook military service with the Swiss army and Olga Taussky-Todd, who had been advised by Heinz Hopf to discuss her work with Stiefel, called in to ETH Zürich on a number of occasions between 1932 and 1937, always finding that Stiefel was on military service.
- At ETH Zürich, Stiefel taught a course on descriptive geometry and geometrical mappings for ten years starting in about 1936.
- However, Stiefel's career changed course completely in 1948.
- Stiefel quickly realized that commercial punched card machines were not suited for mathematical work, and that the electronic computer projects under way, mainly in the US, but also in Britain, would not fill the gap for several years to come.
- However, in 1949, Stiefel heard that Konrad Zuse had built a computer in Germany.
- There followed a series of four papers by Stiefel and his two assistants Heinz Rutishauser and Ambros Speiser, Programmgesteuerte digitale Rechengeräte (elektronische Rechenmaschinen) Ⓣ(Program-controlled digital computing devices (electronic calculators)) appearing in 1950 and 1951.
- Stiefel's team had visited the United States from January 1949 as noted above.
- Stiefel spent the year 1951-52 in the United States attending the Jubilee Symposium of the National Bureau of Standards in August 1951.
- In 1955 the National Bureau of Standards published four lectures by Stiefel under the title Kernel polynomials in linear algebra and their numerical applications.
- In 1961 Stiefel published his most famous work on numerical mathematics entitled Einführung in die numerische Mathematik Ⓣ(Introduction to numerical mathematics).
- In 1959 Numerische Mathematik was founded, the Founding Editors being A S Householder, John Todd, E L Stiefel and A Walther.
- Together with G Scheifele, Stiefel published Linear and regular celestial mechanics.
- The book shows how a mathematician like Stiefel with a deep knowledge of pure mathematics and of the applications of mathematics can bring these together to the benefit of both areas.
- Stiefel received may awards and honours for his wide ranging contributions.

Born 21 April 1909, Zürich, Switzerland. Died 25 November 1978, Zürich, Switzerland.

View full biography at MacTutor

Origin Switzerland

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive