Poisson Summation of Kirillov Orbits.
Polynomially growing pluriharmonic functions on Siegel domains
Let 𝓓 be a symmetric type two Siegel domain over the cone of positive definite Hermitian matrices and let N(Φ)S be a solvable Lie group acting simply transitively on 𝓓. We characterize polynomially growing pluriharmonic functions on 𝓓 by means of three N(Φ)S-invariant second order elliptic degenerate operators.
Property (T) and groups
We show that each group in a class of finitely generated groups introduced in [2] and [3] has Kazhdan’s property (T), and calculate the exact Kazhdan constant of with respect to its natural set of generators. These are the first infinite groups shown to have property (T) without making essential use of the theory of representations of linear groups, and the first infinite groups with property (T) for which the exact Kazhdan constant has been calculated. These groups therefore provide answers...
Property T for discrete groups in terms of their regular representation.
Property (T) for ... Factors and unitary representations of Kazhdan groups.
Propriétés des applications quadratiques d'un espace de Hilbert dans un espace vectoriel. Applications à la théorie spectrale des opérateurs normaux et à l'image numérique d'un opérateur