Date/heure
8 janvier 2026
14:30 - 15:30
Lieu
Salle Döblin
Oratrice ou orateur
Gregory Debruyne (Gent, Belgique)
Catégorie d'évènement Séminaire de Théorie des Nombres de Nancy-Metz
Résumé
Many arguments in mathematics rely on the introduction of an auxiliary function that is compactly supported. Sometimes this compactly supported function is required to satisfy some additional regularity, but this cannot be pushed too far. It can for instance not be analytic as follows by the identity principle.
In this talk, we wish to present a technique that may bypass this obstruction. Namely, instead of considering a single function, we shall construct a sequence of function that are supported in the same compact, and satisfy some good uniform bounds on their derivatives.
This method is a powerful tool as it can, in some circumstances, turn a heuristic argument relying on a compactly supported analytic auxiliary function, into a rigorous proof. As an application, we shall discuss how this technique leads to improvements in some quantified Tauberian theorems.