Czesław Ryll-Nardzewski

Czesław Ryll-Nardzewski (Polish: [ˈt͡ʂɛswaf ˈrɨl narˈd͡zɛfskʲi]; 7 October 1926 – 18 September 2015) was a Polish mathematician.

Czesław Ryll-Nardzewski
Born	(1926-10-07)7 October 1926 Wilno, Second Polish Republic
Died	18 September 2015(2015-09-18) (aged 88) Wrocław,[1] Poland
Nationality	Polish
Known for	Ryll-Nardzewski fixed point theorem Ryll-Nardzewski theorem Kuratowski and Ryll-Nardzewski measurable selection theorem
Scientific career
Fields	Mathematics
Institutions	Wrocław University of Technology Warsaw University
Doctoral advisor	Mieczysław Biernacki[2]

Life and career

Born in Wilno, Second Polish Republic (now Vilnius, Lithuania), he was a student of Hugo Steinhaus. At the age of 26 he became professor at Warsaw University. In 1959, he became a professor at the Wrocław University of Technology. He was the advisor of 18 PhD theses.^[2] His main research areas were measure theory, functional analysis, foundations of mathematics and probability theory. Several theorems bear his name: the Ryll-Nardzewski fixed point theorem,^[3] the Ryll-Nardzewski theorem^[4][5] in model theory, and the Kuratowski and Ryll-Nardzewski measurable selection theorem.^{[6][7][8][9][10]}

He became a member of the Polish Academy of Sciences in 1967.^[1] He died in 2015 at the age of 88^[1][11] and he is buried in Wrocław at Grabiszyński Cemetery [pl].^[12]