Riesz, Frigyes

Born Jan. 22, 1880, in Győr; died Feb. 28, 1956, in Budapest. Hungarian mathematician. Member of the Hungarian Academy of Sciences (1916). Brother of M. Riesz.

Riesz studied in Zürich from 1897 to 1899, in Budapest from 1899 to 1901, in Göttingen, and in Paris from 1903 to 1904. He was a professor at the University of Cluj from 1912 to 1919 and at the University of Szeged from 1920 to 1945. In 1946 he became a professor at the University of Budapest. Riesz’ principal work was in functional analysis. His contributions include the study of linear spaces of integrable functions, the investigation of systems of linear equations with an infinite number of unknowns, and the construction of a theory of functions of operators. He was one of the originators of the theory of topological spaces. In 1922, Riesz founded the journal Acta scientiarum mathematicarum.