A note on quasi -invariant measures on semigroups.
A note on Schrödinger operators with polynomial potentials
A Note on the Amenable Subgroups of PSL (2, R).
A note on the support of right invariant measures.
A note on translates of bounded measures
A notion of open generalized morphism that carries amenability.
A numerical invariant for finitely generated groups via actions on graphs.
A Paley-Wiener theorem for nilpotent Lie groups. (Un théorème de Paley-Wiener pour les groupes de Lie nilpotents.)
A Paley-Wiener theorem for step two nilpotent Lie groups.
It is an interesting open problem to establish Paley-Wiener theorems for general nilpotent Lie groups. The aim of this paper is to prove one such theorem for step two nilpotent Lie groups which is analogous to the Paley-Wiener theorem for the Heisenberg group proved in [4].
A Paley-Wiener theorem on NA harmonic spaces
Let N be an H-type group and consider its one-dimensional solvable extension NA, equipped with a suitable left-invariant Riemannian metric. We prove a Paley-Wiener theorem for nonradial functions on NA supported in a set whose boundary is a horocycle of the form Na, a ∈ A.
A Plancherel measure for the discrete Heisenberg group
A Poisson formula for harmonic projections
A positivity result and normalization of positive convolution structures.
A Proof of Blattner's Conjecture.
A proof of the weak (1,1) inequality for singular integrals with non doubling measures based on a Calderón-Zygmund decomposition.
Given a doubling measure μ on Rd, it is a classical result of harmonic analysis that Calderón-Zygmund operators which are bounded in L2(μ) are also of weak type (1,1). Recently it has been shown that the same result holds if one substitutes the doubling condition on μ by a mild growth condition on μ. In this paper another proof of this result is given. The proof is very close in spirit to the classical argument for doubling measures and it is based on a new Calderón-Zygmund decomposition adapted...
A properly infinite Banach *-algebra with a non-zero, bounded trace
A properly infinite C*-algebra has no non-zero traces. We construct properly infinite Banach *-algebras with non-zero, bounded traces, and show that there are even such algebras which are fairly "close" to the class of C*-algebras, in the sense that they can be hermitian or *-semisimple.
A property for locally convex *-algebras related to property (T) and character amenability
For a locally convex *-algebra A equipped with a fixed continuous *-character ε (which is roughly speaking a generalized F*-algebra), we define a cohomological property, called property (FH), which is similar to character amenability. Let be the space of continuous functions with compact support on a second countable locally compact group G equipped with the convolution *-algebra structure and a certain inductive topology. We show that has property (FH) if and only if G has property (T). On...
A property of a decomposition of weakly almost periodic functions
A property of Fourier Stieltjes transforms on the discrete group of real numbers
Let be a Fourier-Stieltjes transform, defined on the discrete real line and such that the corresponding measure on the dual group vanishes on the set of characters, continuous on . Then for every , has a vanishing interior Lebesgue measure. If the statement is not generally true. The result is applied to prove a theorem of Rosenthal.
À propos des convoluteurs d'un groupe quotient