Seminare und Vorträge im WS 2025/2026
| Date | Lecturer | Seminar | Theme | Time | Location |
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| 28 Apr 2026 | Norihiro Hanihara (Kyushu University) | Abstract representation theory of quivers and spectral Picard groups Abstract. While the (derived) representation theory of quivers over a field is by now well-understood, much less is known when moving to coefficients in the integers or an arbitrary commutative ring. In this talk, we take a rather radical but well-founded approach: it has recently been observed that certain well-known symmetries of categories of representations (tilting results) are actually mere consequences of the stability of the coefficients involved, and so they exist in a much broader generality, often for the corresponding representations in any stable homotopy theory — this includes arbitrary rings, schemes, dg algebras, or ring spectra. For a finite acyclic quiver Q, we present here a method for producing universal autoequivalences of representations C^Q in any stable ∞-category C, which are the elements of the spectral Picard group of Q. This is based on an abstract equivalence of C^Q with a certain mesh ∞-category of representations of the Auslander–Reiten quiver Γ_Q. Then our universal equivalences arise from symmetries of Γ_Q, and thus yield abstract versions of key functors in classical representation theory — e.g. the Auslander-Reiten translation, the Serre functor, etc. Moreover, for representations of trees this allows us to realize the whole derived Picard group over a field as a factor of the spectral Picard group. | Tuesday, 3pm Time Zone Berlin, Rome, Paris | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) |
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| 29 Apr 2026 | Andrea Solotar (University of Buenos Aires, Argentina) | Algebraic versions of T² and of P¹×P¹ and Hochschild cohomology Abstract. We analyze the Hochschild cohomology of triangular algebras that capture some aspects of the geometry and topology of the torus and of P¹×P¹, as well as of the deformations of these algebras. In particular, this shows that the cup product in the Hochschild cohomology of a triangular algebra generally does not follow the intuition from monomial algebras. Our examples also demonstrate that the Hochschild cohomology of a deformation of an algebra may not undergo a reduction of dimension but still have a different cup product structure, and that the Hochschild cohomologies of the deformations of two derivatively equivalent algebras can exhibit remarkably different behaviors. This is a joint work with Vladimir Dotsenko. | Wednesday 2pm–3pm Time Zone Berlin, Rome, Paris | Register to obtain the Zoom link: Lagoon Seminar |
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| 05 May 2026 | Vladimir Dotsenko (Université de Strasbourg) | Yamaguti algebras, noncrossing partitions, and sl_2 Abstract: Among various types of algebras originating in differential geometry, those known as Lie-Yamaguti algebras still remain somewhat mysterious algebraically. Last year, A.Das introduced their 'associative' version, the Yamaguti algebras, which are supposed to serve as envelopes of Lie-Yamaguti algebras. I'll report on joint work with Frédéric Chapoton, which exhibits relationships between this algebraic structure, combinatorics of noncrossing partitions, and the Lie algebra sl_2. | Tuesday, 2pm Time Zone Berlin, Rome, Paris in person | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) |
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| 12 May 2026 | Timothy Logvinenko (Cardiff University) | tba | Tuesday, 3pm Time Zone Berlin, Rome, Paris in person | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) | |
| 27 May 2026 | Pelle Steffens (Technical University of Munich, Germany) | Wednesday 2pm–3pm Time Zone Berlin, Rome, Paris | Register to obtain the Zoom link: Lagoon Seminar |
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| 19 May 2026 | Kevin Schlegel (Universität Bielefeld) | tba | Tuesday 3pm Time Zone Berlin, Rome, Paris in person | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) | |
| 26 May 2026 | Panagiotis Kostas (Aristotle University) | Intrinsic homological algebra for triangulated categories Abstract: In this talk we introduce homological notions -- such as finite global dimension and gorensteinness -- for compactly generated triangulated categories. We observe that the latter generalise classical notions from homological algebra and study those same attributes for other triangulated categories of interest in representation theory, such as the homotopy category of injectives of an Artin algebra or the derived category of a dg algebra. This is based on joint work with C. Psaroudakis and J. Vitória. | Tuesday 3pm Time Zone Berlin, Rome, Paris in person | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) | |
| 03 Jun 2026 | Neeman Amnon (Università degli Studi di Milano Statale) | tba | Wednesday 4:30pm Time Zone Berlin, Rome, Paris in person | Hörsaal Room 203 | |
| 14 Jul 2026 | Ryu Tomonaga (The University of Tokyo) | tba | Tuesday, 3pm Time Zone Berlin, Rome, Paris in person | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) | |
| 21 Jul 2026 | Mika Jäderberg (Linköpings Universitet) | tba | Tuesday, 3pm Time Zone Berlin, Rome, Paris in person | Stefan Cohn-Vossen Raum (Nr. 313 on floor 3) |