Mean separations in Banach spaces under abstract interpolation and extrapolation

Weak Interpolation in Banach 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 ...

Mean Periodic Functions in Banach Spaces

Here we give a necessary and sufficient condition for a Banach space to be separable.

Abstract Hardy-Sobolev spaces and interpolation

Hardy-Sobolev spaces and interpolation N. Badr Institut Camille Jordan Université Claude Bernard Lyon 1 UMR du CNRS 5208 F-69622 Villeurbanne Cedex [email protected] F. Bernicot Laboratoire de Mathématiques Université de Paris-Sud UMR du CNRS 8628 F-91405 Orsay Cedex [email protected] October 19, 2010 Abstract The purpose of this work is to describe an abstract theory of Ha...

Complex 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 ...