Variable Hilbert scales are an important tool for the recent analysis of inverse problems in Hilbert spaces, as these constitute a way to describe smoothness of objects other than ...
We obtain optimal trigonometric polynomials of a given degree N that majorize, minorize and approximate in L1(R/Z) the Bernoulli periodic functions. These are the periodic analogue...
In this paper we give a simple characterization of weighted Sobolev spaces (with piecewise monotonous weights) such that the multiplication operator is bounded: it is bounded if an...
We use a generalization of Wiener's 1/f theorem to prove that for a Gabor frame with the generator in the Wiener amalgam space W (L , 1 )(Rd ), the corresponding frame operato...
It is well known that if a finite order linear differential operator with polynomial coefficients has as eigenfunctions a sequence of orthogonal polynomials with respect to a posi...