## Award Ceremony for the 2024 Barbara and Jaroslaw Zemánek Prize

We cordially invite everyone to the award ceremony for the Barbara and Jaroslav Zemánek Prize in the field of functional analysis, which will take place as part of the IMPAN Colloquium at the Institute of Mathematics of the Polish Academy of Sciences (IMPAN) on October 30th, 2024, at 2:15 PM in room 321 (third floor).

**Programme of the ceremony:**

14:15-15:15 Introductory lecture by Stuart White (University of Oxford)

15:15-15:45 Award of the Prize and a coffee break

15:45–16:45 Lecture of the laureate Christopher Schafhauser (University of Nebraska–Lincoln)

**Abstracts:**

**Stuart White
Title: Introduction to the classification of simple nuclear C*-algebras**

**Abstract:** In this talk, I'll give an introduction to simple nuclear C*-algebras and their classification. This will be illustrated by examples coming from group actions. My aim will be to describe at a high level the paradigm shift from using internal structure to classify, to obtaining internal structure from classification that Chris Schafhauser's work made possible. No prior knowledge of operator algebras will be assumed.

**Christopher Schafhauser
Title:** Lifting problems in C*-algebras and applications

**Abstract: **A classical problem of Halmos asks which essentially normal operators (those commuting with their adjoint modulo a compact operator) on Hilbert space are compact perturbations of normal operators (those commuting with their adjoint). A complete solution was obtained by Brown, Douglas, and Fillmore in the early 70s, and their solution led to the introduction of algebraic topological methods in operator algebras. In particular, for a compact metric space X, they considered all embeddings of C(X) into the quotient B(H)/K(H) of bounded operators on a Hilbert space modulo the compact operators and showed that homotopy classes of such embeddings form an abelian group K_1(X), which is the degree one term for a generalized homology theory dual to topological K-theory. Building on this, Kasparov developed a much more general extension theory, studying lifting problems along more general quotient maps up to a stabilized notion of homotopy. I will discuss some recent progress in `non-stable’ extension theory with applications to embedding problems and classification problems for simple nuclear C*-algebras.