Déformations isospectrales sur certaines nilvariétés et finitude spectrale des variétés de Heisenberg
Degree theory for VMO maps on metric spaces
We construct a degree theory for Vanishing Mean Oscillation functions in metric spaces, following some ideas of Brezis & Nirenberg. The underlying sets of our metric spaces are bounded open subsets of and their boundaries. Then, we apply our results in order to analyze the surjectivity properties of the -harmonic extensions of VMO vector-valued functions. The operators we are dealing with are second order linear differential operators sum of squares of vector fields satisfying the hypoellipticity...
Dense decompositions of locally compact groups
Dense Ideals of Group Algebras.
Densité harmonique et espaces de Banach invariants par translation ne contenant pas
Dependence results on almost periodic and almost automorphic solutions of evolution equations.
Dérivation sur un groupe localement compact et abélien
Derivations into iterated duals of Banach algebras
We introduce two new notions of amenability for a Banach algebra A. The algebra A is n-weakly amenable (for n ∈ ℕ) if the first continuous cohomology group of A with coefficients in the n th dual space is zero; i.e., . Further, A is permanently weakly amenable if A is n-weakly amenable for each n ∈ ℕ. We begin by examining the relations between m-weak amenability and n-weak amenability for distinct m,n ∈ ℕ. We then examine when Banach algebras in various classes are n-weakly amenable; we study...
Des produits de Riesz comme mesures spectrales
Describing Functions: Atomic Decompositions Versus Frames.
Designing Local Orthogonal Bases on Finite Groups I: Abelian Case.
Designing Local Orthogonal Bases on Finite Groups II: Nonabelian Case.
Die Existenz einer Lévy-Abbildung auf einem homogenen Raum.
Die Frobeniuseigenschaft FP für diskrete Gruppen.
Die Resolvente von ... Auf symmetrischen Räumen vom nichtkompakten Typ.
Die unzerlegbaren Charaktere einiger diskreter Gruppen.
Difference functions of periodic measurable functions
We investigate some problems of the following type: For which sets H is it true that if f is in a given class ℱ of periodic functions and the difference functions are in a given smaller class G for every h ∈ H then f itself must be in G? Denoting the class of counter-example sets by ℌ(ℱ,G), that is, , we try to characterize ℌ(ℱ,G) for some interesting classes of functions ℱ ⊃ G. We study classes of measurable functions on the circle group that are invariant for changes on null-sets (e.g. measurable...
Differences of Functions and Group Generators for Compact Abelian Groups.
Differences of functions in locally convex spaces and applications to almost periodic and almost automorphic functions