The following is our current schedule, but see here for previous talks.

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Speaker: Andrei Konovalov
Date: 16 March 2026, 4pm CET
Title: Algebraic K-theory of singular hypersurfaces

Abstract

Considering short exact sequences of enhanced triangulated categories naturally leads to the notion of algebraic K-theory. Although recent years have seen substantial progress in the area, there are still few complete computations of (higher) K-theory of singular varieties: in positive characteristic there are essentially none in dimension >1 in the literature, and the situation in characteristic 0 is not much better. In this talk, I will show how recent developments in algebraic K-theory can be used to understand the K-theory of singular varieties, focusing on cubic surfaces and threefolds, where complete computations can be obtained in many cases.

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Speaker: Amal Mattoo
Date: 30 March 2026, 4pm CEST
Title: Phantoms on Rational Surfaces

Abstract

Phantom categories, or admissible subcategories on which all additive invariants vanish, were once considered pathological phenomena unlikely to occur on simple enough varieties. So when Krah constructed a phantom on a blowup of $\mathbf{P}^{2}$, it came as a surprise and disproved several conjectures! Since then, there has been work on extending this construction to other rational surfaces. In this talk, I will explain these constructions and how they are proved using Kuznetsov's machinery of heights. I will also describe some tools used to study these phantoms, like Hochschild cohomology and a spectral sequence for computing Hom's between objects.

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Speaker: Dave Murphy
Date: 13 April 2026, 4pm CEST
Title: TBA

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Speaker: Gopinath Sahoo
Date: 27 April 2026, 4pm CEST
Title: TBA

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Speaker: Giovanna Le Gros
Date: 4 May 2026, 4pm CEST
Title: TBA

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Speaker: Lukas Bertsch
Date: 11 May 2026, 4pm CEST
Title: TBA

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Speaker: Daigo Ito
Date: 25 May 2026, 4pm CEST
Title: TBA

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Speaker: Fei Peng
Date: 8 June 2026, 4pm CEST
Title: TBA

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