The Ryll-Nardzewski Prize is awarded to Marcin Sabok from McGill University 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 ‘remembering’ the structure of that space, and use in a key step a selection theorem due to Ryll-Nardzewski.

The winner of the Early Career Ryll-Nardzewski Prize is Serhii Bardyla from University of Vienna. The prize was awarded in recognition of solving several difficult problems in general topology, set theory and algebra and his versatile research in these fields. Among the problems solved by the laureate are the problem of Sakai concerning the existence of a C_p(X) space which is a Pytkeev space but not a Frechet–Uryshon space, a long-standing problem of Gerlits and Nagy concerning the existence of delta-sets which are not gamma-sets, the problem of Tzannes concerning the existence of special rigid spaces.

The award ceremony and laureates' lectures will take place on September 9, 2026, as a part of the Ryll-Nardzewski Day — the third day of the international conference Chilean–Polish Mathematical Meeting.