Arbre De Noël de la Géométrie Non-Commutative

NOVEMBER 12–14, 2026 / LABORATOIRE DE MATHÉMATIQUES DE REIMS

REGISTRATION IS FREE BUT MANDATORY !!!

ORGANIZERS:

• Hervé Oyono-Oyono (Université de Lorraine)
• Victor Gayral (Université de Reims Champagne-Ardenne)
• Christelle Marion (Université de Reims Champagne-Ardenne)
• Guillaume Dollé (Université de Reims Champagne-Ardenne)

SCIENTIFIC PROGRAM:

Mini-course #1: Pierre Clare

Title: C*-algebraic Plancherel theorems

Abstract: The noncommutative geometry approach to the representation theory of groups allows to view spaces of representations as the spectra of certain C*-algebras, the study of which can in turn shine a
 light on the topology and the geometry of these spaces.  In these two talks, I will review classical results describing the structure of reduced C*-algebras relevant to the representation theory of real and p-adic reductive groups, before presenting more recent results involving C*-algebras introduced in the context of harmonic analysis on homogeneous spaces, as well as automorphic representation theory.

Mini-course #2: Magnus Goffeng

Title: Poisson transforms and the Baum-Connes conjecture

Abstract: We discuss Poisson transforms for semisimple Lie groups, and in particular Knapp-Wallach’s Szegö maps from the boundary of a symmetric space to its interior. The study of Poisson transforms is motivated by Julg’s program to prove the Baum-Connes conjecture with coefficients in real rank one and to prove the remaining open conjecture of Julg needed to conclude the Baum-Connes conjecture with coefficients in real rank one.  We will discuss a method to produce operators in the Heisenberg calculus, and use that to prove sharp mapping properties for the Szegö maps and compactness of commutators with functions on the Furstenberg boundary. Based on joint work with Heiko Gimperlein.

Rest of the program: under construction