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C*-superrigidity

Jakub Curda (Oxford University)
Thursday 12 November 2026 16:00 – 17:00 Aud. D2 (1531-119)
Mathematics Seminar

A group G is called C*-superrigid if there is no other group with an isomorphic reduced C*-algebra. In 2010, Ioana, Popa and Vaes asked whether every discrete countable torsion-free group is C*-superrigid. In this talk, I will give an overview of the known examples of C*-superrigid groups and add certain classes of virtually abelian groups to the list. Finally, I will answer the question above by presenting examples of torsion-free groups which are not C*-superrigid. The proof uses recent results from classification theory of C*-algebras. This talk is based on several projects joint with subsets of Hua, Knudby, Raum, Slutsky, Thiel and White.

Organised by: AOA
Contact: Johannes Christensen Revised: 09.11.2026