GRAZP 2024 seminar at IHP

This weekly research seminar is a part of the trimester at IHP,  Group actions and Rigidity: Around Zimmer program. 


The seminar will take place in IHP.  Typically, the seminar will be held on Monday and/or Wednesday at 3 pm or 3:30 pm.  Please check below for the exact time of each talk.

Organizers: Homin Lee and Thang Nguyen

List of talks

Week of April 22


Time: 3 pm
Title: Finite Fourier transform.

Abstract:

On a cyclic group of prime order, the non-principal Dirichlet characters together with their Fourier transforms are functions that vanish at 0 and whose modulus is constant outside 0. Do there exist other functions with these properties? I will explain the history of this question and give a positive answer for non-safe primes. The proof relies on Floer homology.

Week of May 6


Time: 3 pm
Title: TBA

Week of May 13

Time: 2 pm (unusual time)

Title: TBA

Time: 3 pm


Title: TBA

Week of May 20

Week of June 3


Time: 3:30 pm
Title: TBA

Week of June 17


Time: 3:30 pm 
Title: Local rigidity of actions of isometries on compact real analytic Riemannian manifolds
Abstract: In this work in collaboration with Z. Zhao (Nice), we consider analytic perturbations of isometries of an analytic Riemannian manifold $M$. We prove that, under some conditions, a finitely presented group of such small enough perturbations is analytically conjugate on $M$ to the same group of isometry it is a perturbation of. Our result relies on a ``Diophantine-like" condition, relating the actions of the isometry group and the eigenvalues of the Laplace-Beltrami operator. Our result generalizes Arnold-Herman's theorem about diffeomorphisms of the circle that are small perturbations of rotations.

Week of June 24

Title: TBA

Title: TBA

Week of July 1

Last updated: April 4, 2024