Interpolation in harmonic Hilbert spaces

Minimal Norm Interpolation in Harmonic Hilbert Spaces and Wiener Amalgam Spaces on Locally Compact Abelian Groups

The family of harmonic Hilbert spaces is a natural enlargement of those classical L2-Sobolev space on Rd which consist of continuous functions. In the present paper we demonstrate that the use of basic results from the theory of Wiener amalgam spaces allows to establish fundamental properties of harmonic Hilbert spaces even if they are defined over an arbitrary locally compact abelian group G. ...

Complex Interpolation and Twisted Twisted Hilbert Spaces

Interpolation between Hilbert , Banach and Operator spaces

Motivated by a question of Vincent Lafforgue, we study the Banach spaces X satisfying the following property: there is a function ε → ∆ X (ε) tending to zero with ε > 0 such that every operator T : L 2 → L 2 with T ≤ ε that is simultaneously contractive (i.e. of norm ≤ 1) on L 1 and on L ∞ must be of norm ≤ ∆ X (ε) on L 2 (X). We show that ∆ X (ε) ∈ O(ε α) for some α > 0 iff X is isomorphic to ...

On Interpolation and Sampling in Hilbert Spaces of Analytic Functions

In this paper we give new proofs of some theorems due to Seip Seip Wallst en and Lyubarskii Seip on sequences of interpolation and sampling for spaces of analytic functions that are square integrable with respect to certain weights The results are also given in a somewhat more general setting Introduction In a series of recent papers Seip S Seip Wallst en S W and Lyuabarskii Seip L S have studi...

Interpolation and harmonic majorants in big Hardy-Orlicz spaces

Free interpolation in Hardy spaces is characterized by the well-known Carleson condition. The result extends to Hardy-Orlicz spaces contained in the scale of classical Hardy spaces H, p > 0. For the Smirnov and the Nevanlinna classes, interpolating sequences have been characterized in a recent paper in terms of the existence of harmonic majorants (quasi-bounded in the case of the Smirnov class)...