Giovedì 12 Dicembre 2024 alle ore 11:00, nel quadro del ciclo di seminari Al@Bicocca, Giada Serafini (Università di Düsseldorf) parlerà di
Titolo: Profinite properties of ℓ2-invariants
Abstract: Although higher ℓ2-Betti numbers bn(2), n ≥ 2 are in general not profinite invariants, some interesting information on the ℓ2-cohomology of S-arithmetic groups still seems to be preserved under profinite commensurability. This leads us to prove a stability result for another ℓ2-invariant strictly related to the ℓ2-Betti numbers: the sign of the Euler characteristic, which indeed can be seen as the alternating sum of such bn(2). In this talk we will introduce the basics and motivations for being interested in Profinite rigidity and then we will discuss the key steps needed to prove our result for S-arithmetic groups in terms of local-global principles in the setting of Galois cohomology.
All of this is joint work with Holger Kammeyer.
Informazioni per partecipare
Il seminario si terrà in Aula 3014 (3° Piano) - Edificio U5, Università degli Studi di Milano-Bicocca e sarà disponibile anche online al seguente link Webex