News
Professor Marcin Sabok awarded the Ryll-Nardzewski Prize (2026)
Published: 20 March 2026
We are delighted to announce that Marcin Sabok has been awarded the Ryll-Nardzewski Prize.
The prize was established to honour the great Polish mathematician Czes艂aw Ryll-Nardzewski, and is awarded by the Ryll-Nardzewski Center at Wroc艂aw University of Science and Technology. The prize is for outstanding achievements in mathematics in areas related to the work of Ryll-Nardzewski.
馃敆
The Ryll-Nardzewski Prize is awarded to Marcin Sabok from 海角社区 in recognition of his proof that the Borel complexity of the isomorphism problem for separable C*-algebras coincides with that of the universal orbit equivalence relation. The result answered an important question in the descriptive set theory of complexity, completing a circle of ideas due to Farah, Hjorth, Kechris and other mathematicians. The arguments of Sabok rely on an ingenious construction, which for a given bounded perfect Polish metric space produces a Choquet simplex 鈥榬emembering鈥� the structure of that space, and use in a key step a selection theorem due to Ryll-Nardzewski.