Next talk on Sunday, April 28th, 2024 at 6 pm (Paris time) 

Title: (Symplectic) Determinant laws

Speaker: Mohamed Moakher, Université Sorbonne Paris Nord

Abstract. The notion of pseudo-representations was initially introduced for group algebras by Wiles (for GL2) and by Taylor (for GLd) in order to construct Galois representations associated to certain automorphic forms. Chenevier proposed an alternative theory of "determinant laws" which extends Wiles and Taylor’s definition to arbitrary rings. This theory has proved to be useful in the study of congruences between automorphic forms and in the deformation theory of residually reducible Galois representations. 

In the first part of this talk, I will introduce this theory and highlight its main properties, aiming to illustrate its role in the study of moduli of Galois representations.

In the second part of the talk, I will present my joint work with Julian Quast on symplectic determinant laws, which adapts Chenevier’s framework to the symplectic group GSp2d. 

  ************************************Upcoming**********************************

• May 26th: Sami Douba (IHES) TBA