André Haefliger Scientist

André Haefliger (born 22 May 1929) is a Swiss mathematician who works primarily on topology.He studied mathematics in Lausanne. He received his PhD in 1958 from the University of Strasbourg under the supervision of Charles Ehresmann with "Structures feuilletées et cohomologie à valeurs dans un faisceau de groupoides".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.Haefliger made important contributions to topology, for example, in knot theory and the theory of foliations, where he introduced Haefliger structures. In 1956, he also found the topological obstruction to the existence of a spin structure on an orientable Riemannian manifold.In 1974-75, he was President of the Swiss Mathematical Society.He is an honorary doctor of ETH Zurich (1992).His students include Vaughan Jones.