Who developed one of the foundations of functional analysis and also taught Hugo Steinhaus?
David Hilbert David Hilbert (] ; 23 January 1862 – 14 February 1943) was a German mathematician. He is recognized as one of the most influential and universal mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas in many areas, including invariant theory and the axiomatization of geometry. He also formulated the theory of Hilbert spaces, one of the foundations of functional analysis.
Julius Ebbinghaus Julius Ebbinghaus (9 November 1885, Berlin – 16 June 1981, Marburg an der Lahn) was a German philosopher, one of the closest followers of Immanuel Kant active in the twentieth century. He was influenced by the Heidelberg school of neo-Kantianism of Wilhelm Windelband, and wrote on philosophy of law and the categorical imperative. Professor at Marburg University (Philipps-Universität Marburg) since 1940; 1954 professor emeritus, continuing lectures until 1966. In October 1945, he became installed as Rector Magnificus by order of the American occupation forces. He was the son of famous psychologist Hermann Ebbinghaus.