Séminaires : Séminaire Variétés Rationnelles

Equipe(s) : tga,
Responsables :Cyril Demarche et Mathieu Florence
Email des responsables :
Salle :
Adresse :Campus Pierre et Marie Curie
Description

 

Le séminaire a généralement lieu à Jussieu (Sorbonne Université, Paris), un vendredi par mois, entre 14h30 et 17h.

http://math.univ-lyon1.fr/homes-www/gille//sem/sem_variete_archives.html


Orateur(s) André Macedo - Reading,
Titre Local-global principles for norm equations.
Date10/04/2020
Horaire15:30 à 16:30
Diffusion
Résume

Given an extension L/K of number fields, we say that the Hasse norm principle (HNP) holds if every non-zero element of K which is a norm everywhere locally is in fact a global norm from L. If L/K is cyclic, the original Hasse norm theorem states that the HNP holds. More generally, there is a cohomological description (due to Tate) of the obstruction to the HNP for Galois extensions. In this talk, I will present work (joint with Rachel Newton) developing explicit methods to study this principle for non-Galois extensions. As a key application, I will describe how these methods can be used to characterize the HNP for extensions whose normal closure has Galois group A_n or S_n. I will additionally discuss some recent generalizations of these methods to study the Hasse principle and weak approximation for multinorm equations as well as consequences in the statistics of these local-global principles.

Sallecode d'accès : écrire à Cyril Demarche
Adressehttps://bigbluebutton.imj-prg.fr/b/cyr-94x-zup
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