100, rue des maths 38610 Gières / GPS : 45.193055, 5.772076 / Directeur : Louis Funar

Oussama Hamza

An isotypical study of filtrations on pro-$p$ group
Vendredi, 17 Juin, 2022 - 16:00 à 17:00
Résumé : 
During the 60's, Jennings, Golod, Shafarevich and Lazard introduced two sequences of integers $(a_n)$ and $(c_n)$, closely related to a special filtration of a finitely generated pro-$p$ group $G$, called Zassenhaus filtration. These sequences give the cardinality of $G$, and characterize its topology. Let us cite the famous Gocha's alternative: this is a condition on $(a_n)$ and $(c_n)$ equivalent for G to be analytic, i.e a Lie group over $p$-adic fields. Recently, in 2016, Minac, Rogelstad and Tan inferred an explicit relation between $(a_n)$ and $(c_n)$.
This talk will review these results, then considering geometrical ideas of Filip and Stix, we enrich them in an isotypical context, i.e when there exists a finite group $\Delta \subset Aut(G)$ of order a prime $q$ dividing $p-1$.

We also study the analoguous case given by lower central series, and give several examples.

Institution de l'orateur : 
Western University (Ontario)
Thème de recherche : 
Salle : 
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