Séminaire Arithmétique et géométrie algébrique
organisé par l'équipe Arithmétique et géométrie algébrique
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Cécile Gachet
Equivariant descent for the birational finiteness properties of certain Calabi—Yau pairs
19 mars 2026 - 14:00Salle de séminaires IRMA
In dimension 3 and higher, it is well-known that certain singular complex projective varieties do not admit a unique minimal resolution of singularities. Typically, there are small birational modifications which allow to toggle back and forth between different minimal models of the same variety. This framework is particularly well-understood for Calabi—Yau pairs, whose minimal models are connected by finite sequences of so-called flops. Some finite sequences of flops loop, and thereby define non-trivial birational automorphisms on one model; to that extent, it is not uncommon for a Calabi-Yau pair to have infinitely many marked minimal models. It is however conjectured that a klt Calabi—Yau pair has finitely many unmarked minimal models. As the class of klt Calabi—Yau pairs is naturally closed under quotients by finite group actions, it is reasonable to expect birational finiteness properties to descend under finite quotient. In that spirit, this talk presents a descent result for birational finiteness properties of a large class of varieties, both under the action of a finite group and under the action of the Galois group of a perfect field. We will provide examples and applications along the way. -
Andrea Gallese
tbd
2 avril 2026 - 14:00Salle de séminaires IRMA
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German Stefanich
tbd
9 avril 2026 - 14:00Salle de séminaires IRMA