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
Differential operators of gradient type associated with spherical harmonics
Differential operators on equivariant vector bundles over symmetric spaces.
Dilations associated to flat curves.
I would like to give an exposition of the recent work of Tony Carbery, Mike Christ, Jim Vance, David Watson and myself concerning Hilbert transforms and Maximal functions along curves in R2 [CCVWW].
Dilations of Hilbert space operators (General theory) [Book]
Dimensions of components of tensor products of representations of linear groups with applications to Beurling-Fourier algebras
We give universal upper bounds on the relative dimensions of isotypic components of a tensor product of representations of the linear group GL(n) and universal upper bounds on the relative dimensions of irreducible components of a tensor product of representations of the special linear group SL(n). This problem is motivated by harmonic analysis problems, and we give some applications to the theory of Beurling-Fourier algebras.
Diophantine Approximation in certain Solenoids
Dirac operators, conformal transformations and aspects of classical harmonic analysis.
Direct sums of spaces of functions on semigroups.
Directionally Euclidean structures of Banach spaces
We study Banach spaces with directionally asymptotically controlled ellipsoid-approximations of the unit ball in finite-dimensional sections. Here these ellipsoids are the unique minimum volume ellipsoids, which contain the unit ball of the corresponding finite-dimensional subspace. The directional control here means that we evaluate the ellipsoids by means of a given functional of the dual space. The term 'asymptotical' refers to the fact that we take 'lim sup' over finite-dimensional subspaces. ...
Dirichlet forms on symmetric spaces
Let be a locally compact group and a compact subgroup such that the algebra of biinvariant integrable functions is commutative. We characterize the -invariant Dirichlet forms on the homogeneous space using harmonic analysis of . This extends results from Ch. Berg, Séminaire Brelot-Choquet-Deny, Paris, 13e année 1969/70 and J. Deny, Potential theory (C.I.M.E., I ciclo, Stresa), Ed. Cremonese, Rome, 1970. Every non-zero -invariant Dirichlet form on a symmetric space of non compact type...
Dirichlet problem with L-boundary data in contractible domains of Carnot groups
Let be a sub-laplacian on a stratified Lie group . In this paper we study the Dirichlet problem for with -boundary data, on domains which are contractible with respect to the natural dilations of . One of the main difficulties we face is the presence of non-regular boundary points for the usual Dirichlet problem for . A potential theory approach is followed. The main results are applied to study a suitable notion of Hardy spaces.