Séminaire Arithmétique et géométrie algébrique
organisé par l'équipe Arithmétique et géométrie algébrique
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Josh Lam
p-curvatures and non-abelian cohomology
28 mai 2026 - 14:00Salle de séminaires IRMA
The study of non-abelian cohomology was pioneered by Simpson in the 90s, and is, broadly speaking, the study of representations of the fundamental groups of algebraic varieties; on the other hand, many questions on this subject were already studied in the early 1900s by mathematicians such as Painlevé, Garnier, and Schlesinger. As for usual cohomology, there are many different realizations of non-abelian cohomology, such as Betti, de Rham, étale, and even crystalline, leading to a rich interplay between dynamics, differential equations, and arithmetic. I will give an introduction to this topic, focusing on the mod p aspects, and the proof of a conjecture of Bost/Ekedahl--Shepherd-Barron--Taylor in many new cases. This is based on joint work with Daniel Litt. -
Mura Yakerson
tbd
4 juin 2026 - 14:00Salle de séminaires IRMA
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Jürg Kramer
Arithmetic intersections of line bundles with singular metrics
18 juin 2026 - 14:00Salle de séminaires IRMA
In our talk, we will present an extension of arithmetic intersection theory of adelic divisors on quasi-projective varieties introduced by Yuan–Zhang to the case where these divisors are not necessarily arithmetically nef. The key tool to realize this extension is the concept of relative finite energy established by T. Darvas et al.. In particular, our theory will allow to compute heights on mixed Shimura varieties, e. g., the arithmetic self-intersection number of the line bundle of Siegel–Jacobi forms on the universal abelian variety. This is joint work with José Burgos Gil. -
Alessandra Sarti
tbd
25 juin 2026 - 14:00Salle de séminaires IRMA