Czesław Ryll-Nardzewski

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.{{cite web|url=https://www.genealogy.math.ndsu.nodak.edu/id.php?id=65032|title=Mathematics Genealogy Project|access-date=9 February 2021}} 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,{{cite book |last1=Granas|first1=Andrzej|last2=Dugundji|first2=James|date=2003|title=Fixed point theory|url=https://archive.org/details/fixedpointtheory00gran|url-access=limited|series=Springer Monographs in Mathematics|location=New York|publisher=Springer Verlag|pages=[https://archive.org/details/fixedpointtheory00gran/page/n186 171], 172, 174, 196|isbn=0-387-00173-5|doi=10.1007/978-0-387-21593-8|mr=1987179|author2-link=James Dugundji}} “9. Theorem of Ryll-Nardzewski” (p. 171), “(9.6) Theorem (Ryll-Nardzewski)” (p. 174) the Ryll-Nardzewski theorem{{cite book|last=Hodges|first=Wilfrid|date=1993|title=Model theory|series=Encyclopedia of Mathematics and its Applications|volume=42|location=Cambridge|publisher=Cambridge University Press|page=[https://archive.org/details/modeltheory0000hodg/page/341 341]|chapter=7.3 Countable categoricity|mr=1221741|isbn=978-0-521-30442-9|doi=10.1017/CBO9780511551574|author-link=Wilfrid Hodges|chapter-url=https://archive.org/details/modeltheory0000hodg/page/341}} See Theorem 7.3.1{{cite book |last=Cameron|first=Peter J.|date=1990|title=Oligomorphic permutation groups|series=London Mathematical Society Lecture Note Series|volume=152|location=Cambridge|publisher=Cambridge University Press|page=30|chapter=2.5 The Ryll-Nardzewski Theorem|isbn=0-521-38836-8|zbl=0813.20002|mr=1066691|doi=10.1017/CBO9780511549809|author-link=Peter Cameron (mathematician)}} Cf. (2.10) in model theory, and the Kuratowski and Ryll-Nardzewski measurable selection theorem.{{cite book |last=Bogachev|first=Vladimir I.|date=2007|title=Measure theory|volume=II|location=Berlin|publisher=Springer Verlag|pages=36,441|isbn=978-3-540-34513-8|doi=10.1007/978-3-540-34514-5|mr=2267655}} See Theorem 6.9.3 on p. 36 and the historical comment on p. 441{{cite book|last=Kechris|first=Alexander S.|date=1995|title=Classical descriptive set theory|chapter=II. Borel Sets|series=Graduate Texts in Mathematics|volume=156|location=New York|publisher=Springer Verlag|page=[https://archive.org/details/classicaldescrip0000kech/page/76 76]|mr=1321597|doi=10.1007/978-1-4612-4190-4|isbn=0-387-94374-9|author-link=Alexander S. Kechris|chapter-url=https://archive.org/details/classicaldescrip0000kech/page/76}} See Theorem (12.13) at the bottom of p. 76{{cite journal |last1=Cascales|first1=Bernardo|last2=Kadets|first2=Vladimir|last3=Rodríguez|first3=José|date=2010|title=Measurability and selections of multi-functions in Banach spaces|url=http://www.heldermann.de/JCA/JCA17/JCA171/jca17017.htm|journal=Journal of Convex Analysis|volume=17|issue=1|mr=2642727|pages=229–230}} See Theorem A{{cite web |last=Ryll-Nardzewski |first=Czesław |date=1948 |title=List of publication in MathSciNet |url=https://mathscinet.ams.org/mathscinet/search/author.html?mrauthid=152235 |access-date=2021-02-19 |website=MathSciNet |language=en |number=American Mathematical Society}}{{Cite web |title=Czesław Ryll-Nardzewski - Author Profile - zbMATH Open |url=https://zbmath.org/authors/?q=au:Ryll-Nardzewski |access-date=2025-02-03 |website=zbmath.org}}

He became a member of the Polish Academy of Sciences in 1967. He died in 2015 at the age of 88[http://www.ptm.org.pl/zawartosc/zmar%C5%82-profesor-czes%C5%82aw-ryll-nardzewski-1926-2015 Zmarł Profesor Czesław Ryll-Nardzewski] {{in lang|pl}}{{cite journal |last1=Michał|first1=Morayne|date=2016|title=Czesław Ryll-Nardzewski (1926-2015)|doi=10.14708/wm.v52i1.3385|url=https://wydawnictwa.ptm.org.pl/index.php/wiadomosci-matematyczne/article/view/3385/3053|journal= Wiadomości Matematyczne|series=Series II |volume=52|issue=1|mr=3559446|pages=163–165}} and he is buried in Wrocław at {{ill|Grabiszyński Cemetery|pl|Cmentarz Grabiszyński}}.{{cite web|title=Grave record for Czesław Ryll-Nardzewski (7 Oct 1926 - 18 Sep 2015), BillionGraves Record 25205206 Wrocław, wrocławski, dolnośląskie, Poland|url=https://pl.billiongraves.com/grave/Czes%C5%82aw-Ryll-Nardzewski/25205206}}

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• [http://www.instytucja.pan.pl/index.php?option=com_content&view=article&id=1220:ryll-nardzewski-czesaw&catid=50:wydzia-iii&Itemid=30 Short biography] at the Polish Academy of Sciences

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Category:1926 births

Category:2015 deaths

Category:Model theorists

Category:Scientists from Vilnius

Category:People from Wilno Voivodeship (1926–1939)

Category:Polish mathematicians

Category:Recipients of the State Award Badge (Poland)

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