Sur une propriété des suites asymptotiquement inconditionnelles
This paper gives a characterization of surjective isometries on spaces of continuously differentiable functions with values in a finite-dimensional real Hilbert space.
We characterize tauberian operators in terms of the images of disjoint sequences and in terms of the image of the dyadic tree in . As applications, we show that the class of tauberian operators is stable under small norm perturbations and that its perturbation class coincides with the class of all weakly precompact operators. Moreover, we prove that the second conjugate of a tauberian operator is also tauberian, and the induced operator is an isomorphism into. Also, we show that embeds...
A concept of the multiplicator of symmetric function space concerning to projective tensor product is introduced and studied. This allows us to obtain some concrete results. In particular, the well-know theorem of R. O'Neil about boundedness of tensor product in the Lorentz spaces Lpq is discussed.