Marcel Riesz was a Hungarian mathematician, known for work on summation methods, potential theory, and other parts of analysis, as well as number theory, partial differential equations, and Clifford algebras. He spent most of his career in Lund, Sweden.
Riesz c. 1930.
Frigyes Riesz was a Hungarian mathematician who made fundamental contributions to functional analysis, as did his younger brother Marcel Riesz.
Frigyes Riesz