Giovedì 22 Ottobre 2026 dalle ore 11:00, nel quadro del ciclo di seminari Al@Bicocca, Oussama Hamza e Zhizheng Yu (Harbin Institute of Technology) terranno i seguenti interventi
Relatore: Oussama Hamza
Titolo: Filtrations and Graph Products: Applications in Galois Theory and Arithmetic
Abstract: Graph products, filtrations, and cohomology rings provide useful tools for studying pro-p quotients of absolute Galois groups. I will first present my results, with Maire, Mináč, and Tân on formally real Pythagorean fields of finite type (RPF fields). In this work, a new class of groups, called Delta-Right Angled Artin groups, is introduced. This class provides a new necessary condition on pro-2 groups to be pro-2 maximal quotients of absolute Galois groups. I will then discuss pro-p extensions of number fields, when p is an odd prime, with restricted ramification and prescribed splitting. In the wild case (ramification containing places above p), joint work with Lim and Maire uses coproduct decompositions and Massey vanishing property to construct large unipotent extensions. In the tame case (ramification not containing places above p), analogously to knot theory, we have a notion of linking numbers for some of these extensions.
Joint work with Feuerpfeil and Lim answers a question of Labute on the realization of linking numbers and derive several cohomological consequences.
Relatore: Zhizheng Yu
Titolo: Commutator on Banach Spaces
Abstract: In this talk, we will review the historical development of research on commutators on Banach spaces, with a focus on characterizing whether a given Banach space is a Wintner space. Finally, we will demonstrate that Schatten p-spaces Cp, 1 ≤ p < ∞, are Wintner spaces. In particular, an operator T ∈ B(Cp) is a commutator in B(Cp) if and only if T − λI is is not Cp-strictly singular for every λ ≠ 0.
This talk is based on the joint work with L. X. Cheng, J. H. Huang and F. Sukochev.
Informazioni per partecipare
Il seminario si terrà in Aula Alpha (Edificio DB1 | Deutsche Bank | Piazza del Calendario 3, Milano) e sarà possibile partecipare anche online da questo link.
Chi volesse partecipare in presenza, ma fosse impossibilitato ad accedere all'edificio DB1, può contattare gli organizzatori con almeno 24 ore di anticipo all’indirizzo: albicocca@unimib.it
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