Andreas Floer

Andreas Floer was a German mathematician, born in Duisburg in 1956 and died in Bochum in 1991, best known for symplectic topology and mathematical physics and for the theory now named Floer homology. He studied at the Ruhr University Bochum, worked at Berkeley with Clifford Taubes and Alan Weinstein, and took his doctorate at Bochum in December 1984 under Zehnder, working on Arnold's fixed point conjecture for symplectic maps. In 1987 he proved a special case of that conjecture using Morse theory for fixed points of symplectic diffeomorphisms, and he went on to develop instanton homology for three-manifolds using the Chern-Simons function. His central observation was that the difference between the indices of two solutions can still be defined where the index itself is infinite, which lets such solutions be counted. He became full professor at Berkeley in 1990, gave a plenary address at the 1990 International Congress of Mathematicians in Kyoto, and died the following year at the age of thirty four.