Humboldt Arithmetic Geometry Seminar

Humboldt University Berlin, Summer 2025

Time: Tuesdays 15:15 - 16:45

Venue: Room 3.006, Rudower Chaussee 25, 12489 Berlin

— See also the Algebraic Geometry Seminars at HU and FU


NOTE: This semester the seminar will take place from 15:15 - 16:45 !!!
20.05.2025 Marco Maculan (Jussieu, Paris)
Title: Affine vs. Stein in rigid geometry
Abstract: What is the relation between coherent cohomology on a complex variety and that of the associated analytic space? The natural map between them is certainly not surjective for cardinality reasons. It is not even injective in general: this is a consequence of the existence of a nonaffine algebraic variety which is Stein. In a joint work with J. Poineau, we show that over non-Archimedean field the situation is, pun intended, far more rigid.
10.06.2025 Abhishek Oswal (Freiburg)
Title: p-adic hyperbolicity of the moduli space of abelian varieties
Abstract: By a theorem of Borel, any holomorphic map from a complex algebraic variety to the moduli space of abelian varieties (and more generally to an arithmetic variety) is in fact algebraic. A key input is to prove that any holomorphic map from a product of punctured disks to such an arithmetic variety does not have any essential singularities. In this talk, I'll discuss a p-adic analogue of these results. This is joint work with Ananth Shankar and Xinwen Zhu (with an appendix by Anand Patel).
THURSDAY 19.06.2025 Philip Engel (Chicago, Illinois)
Title: Boundedness theorems for abelian fibrations
Abstract: I will report on forthcoming work, joint with Filipazzi, Greer, Mauri, and Svaldi, on boundedness results for abelian fibrations. We will discuss a proof that irreducible Calabi-Yau varieties admitting an abelian fibration are birationally bounded in a fixed dimension; and that Lagrangian fibrations of symplectic varieties, in a fixed dimension, are analytically bounded. Conditional on the generalized semiampleness/hyperkahler SYZ conjecture, this bounds the number of deformation classes of hyperkahler varieties in a fixed dimension, with second Betti number at least 5.
24.06.2025 Denis-Charles Cisinski (Regensburg)
Title: tba
Abstract: tba


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