Ernst Sigismund Fischer, Date of Birth, Place of Birth, Date of Death

Ernst Sigismund Fischer

Austrian mathematician

Date of Birth: 12-Jul-1875

Place of Birth: Vienna, Austria

Date of Death: 14-Nov-1954

Profession: mathematician, university teacher

Nationality: Austria

Zodiac Sign: Cancer

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. He is the grandson of composer Karl Graedener.