André Haefliger Explained

André Haefliger
Birth Date:22 May 1929
Birth Place:Nyon, Switzerland
Nationality:Swiss
Fields:Mathematics
Workplaces:University of Geneva
Alma Mater:University of Lausanne
University of Paris
Thesis Title:Structures feuilletées et cohomologie à valeurs dans un faisceau de groupoides
Thesis Url:https://link.springer.com/article/10.1007/BF02564582
Thesis Year:1958
Doctoral Advisor:Charles Ehresmann
Doctoral Students:Augustin Banyaga
Vaughan Jones
Known For:Haefliger structure
Awards:Leroy P. Steele Prize
Website:https://www.unige.ch/math/folks/haefliger/

André Haefliger (pronounced as /de-CH/; 22 May 19297 March 2023) was a Swiss mathematician who worked primarily on topology.

Education and career

Haefliger went to school in Nyon and then attended his final years at Collège de Genève in Geneva. He studied mathematics at the University of Lausanne from 1948 to 1952. He worked for two years as a teaching assistant at École Polytechnique de l'Université de Lausanne. He then moved to University of Strasbourg, then he followed Charles Ehresmann in Paris, where he received his Ph.D. degree in 1958.[1] His thesis was entitled "Structures feuilletées et cohomologie à valeurs dans un faisceau de groupoïdes" and was written under the supervision of Charles Ehresmann.

Haefliger got a research fellowship for one year at the University of Paris, where he participated in the seminar of Henri Cartan, and then from 1959 to 1961 he worked at the Institute for Advanced Study in Princeton, New Jersey. Since 1962 he has been a full professor at the University of Geneva until his retirement in 1996.[2]

In 1966 Haefliger was invited speaker at the International Congress of Mathematicians in Moscow.[3] In 1974–75, he was president of the Swiss Mathematical Society.[4]

Haefliger obtained a Doctorate honoris causa from the ETH Zurich in 1992 and from the University of Dijon in 1997. In 2020 Haefliger and Martin Bridson were awarded the American Mathematical Society's Leroy P. Steele Prize for Mathematical Exposition, for their book Metric Spaces of Non-Positive Curvature (Springer Verlag, 1999).[5]

Haefliger died on 7 March 2023, at the age of 93.[6]

Research

Haefliger's main research interests were differential topology and geometry.

Haefliger found the topological obstruction to the existence of a spin structure on an orientable Riemannian manifold.[7] In two papers in the Annals he studied various embedding of spheres in relations to knot theory.[8] [9] He has also made important contributions in the theory of foliations, introducing the notion of Haefliger structures.[10]

He wrote more than 80 papers in peer review journals[11] and had 20 Ph.D. students, including Augustin Banyaga and the future Field Medalist Vaughan Jones.

Selected works

External links

Notes and References

  1. Max-Albert Knus, 'André Haefliger', Historical Dictionary of Switzerland, retrieved 22 March 2023.
  2. Web site: Celebratio Mathematica — Haefliger — Jackson. 19 December 2021. celebratio.org. en.
  3. Web site: ICM Plenary and Invited Speakers International Mathematical Union (IMU). 19 December 2021. www.mathunion.org.
  4. Web site: Organisation » Past Presidents The Swiss Mathematical Society. 18 December 2021. www.math.ch.
  5. Web site: News from the AMS. 18 December 2021. American Mathematical Society. en.
  6. Web site: In memoriam André Haefliger . Université de Genève . 9 March 2023 . 12 March 2023.
  7. A. Haefliger. 1956. Sur l'extension du groupe structural d'un espace fibré. C. R. Acad. Sci. Paris. 243. 558–560.
  8. Haefliger. Andre. 1962. Knotted (4k - 1)-Spheres in 6k-Space. Annals of Mathematics. 75. 3. 452–466. 10.2307/1970208. 1970208 . 0003-486X.
  9. Haefliger. Andre. 1966. Differentiable Embeddings of Sn in Sn+q for $q > 2$. Annals of Mathematics. 83. 3. 402–436. 10.2307/1970475. 1970475 . 0003-486X.
  10. Haefliger. A.. 1970. Feuilletages sur les variétés ouvertes. Topology. en. 9. 2. 183–194. 10.1016/0040-9383(70)90040-6.
  11. Web site: zbMATH Open - the first resource for mathematics. 19 December 2021. zbmath.org.