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Department of Applied Mathematics and Theoretical Physics

For d≥4 and p a sufficiently large prime, we construct a lattice Γ≤PSp2d(ℚp), such that its universal central extension cannot be sofic if Γ satisfies some weak form of stability in permutations. In the proof, we make use of high-dimensional expansion phenomena. A key ingredient are new cohomological obstructions to weak containment of actions.

Further information

Time:

26Nov
Nov 26th 2025
10:15 to 11:15

Venue:

Seminar Room 1, Newton Institute

Speaker:

Andreas Thom (Technische Universität Dresden)

Series:

Isaac Newton Institute Seminar Series