Czesław Ryll-Nardzewski


Czesław Ryll-Nardzewski was a Polish mathematician.
Born in Wilno, Second Polish Republic, he was a student of Hugo Steinhaus. At the age of 26 he became professor at the Warsaw University. In 1959, he became a professor at the Wrocław University of Technology. The advisor of many PhD. His main research areas are measure theory, functional analysis, foundations of mathematics and probability theory. Several theorems bear his name: the Ryll-Nardzewski fixed point theorem, the Ryll-Nardzewski theorem in model theory, and the Kuratowski and Ryll-Nardzewski measurable selection theorem.
He became a member of the Polish Academy of Sciences in 1967. He died in 2015 at the age of 88 and he is buried in the Wrocław, cm. Grabiszyński.