Ernst Sigismund Fischer (12 July 1875 – 14 November 1954) was a mathematician born in Vienna, Austria. He worked alongside both Mertens and Minkowski at the Universities of Vienna and Zurich, respectively. He later became professor at the University of Erlangen, where he worked with Emmy Noether.
His main area of research was mathematical analysis, specifically orthonormal sequences of functions which laid groundwork for the emergence of the concept of a Hilbert space.
The Riesz–Fischer theorem in Lebesgue integration is named in his honour.
Famous quotes containing the word fischer:
“Man, became man through work, who stepped out of the animal kingdom as transformer of the natural into the artificial, who became therefore the magician, man the creator of social reality, will always stay the great magician, will always be Prometheus bringing fire from heaven to earth, will always be Orpheus enthralling nature with his music. Not until humanity itself dies will art die.”
—Ernst Fischer (1899–1972)