Über die spektralen Vielfachheitsfunktionen des Multiplikationsoperators
Über eine Klasse symmetrischer idealer Funktionenräume nebst Anwendungen
Über Kommutatoren und Störungsmetriken und ihre Beziehung zum Funktionalkalkül.
Un espace de Banach réticulé qui a presque la propriété de Radon-Nikodym
Une remarque sur un théorème de Bourgain
Uniform bounds for the bilinear Hilbert transforms (II).
We continue the investigation initiated in [Grafakos, L. and Li, X.: Uniform bounds for the bilinear Hilbert transforms (I). Ann. of Math. (2)159 (2004), 889-933] of uniform Lp bounds for the family of bilinear Hilbert transformsHα,β(f,g)(x) = p.v. ∫R f(x - αt) g (x - βt) dt/t.
Uniform Convergence of Operators on L... and Similar Spaces.
Uniform estimates for some paraproducts.
Uniform ordered spectral decompositions
Uniformly bounded composition operators in the banach space of bounded (p, k)-variation in the sense of Riesz-Popoviciu
We prove that if the composition operator F generated by a function f: [a, b] × ℝ → ℝ maps the space of bounded (p, k)-variation in the sense of Riesz-Popoviciu, p ≥ 1, k an integer, denoted by RV(p,k)[a, b], into itself and is uniformly bounded then RV(p,k)[a, b] satisfies the Matkowski condition.
Uniformly summing sets of operators on spaces of continuous functions.
Unimodular Eigenvalues and Invariant Measures for Linear Operators.
Universal interpolating sequences on some function spaces
Let be the Hilbert space with reproducing kernel . This paper characterizes some sufficient conditions for a sequence to be a universal interpolating sequence for .
Universal Taylor series with maximal cluster sets.
Universality of derivative and antiderivative operators with holomorphic coefficients
We prove some conditions on a sequence of functions and on a complex domain for the existence of universal functions with respect to sequences of certain derivative and antiderivative operators related to them. Conditions for the equicontinuity of those families of operators are also studied. The conditions depend upon the "size" of the domain and functions. Some earlier results about multiplicative complex sequences are extended.
Universally divergent Fourier series via Landau's extremal functions
We prove the existence of functions , the Fourier series of which being universally divergent on countable subsets of . The proof is based on a uniform estimate of the Taylor polynomials of Landau’s extremal functions on .