A topological characterization of the product of two closed operators
The purpose of this work is to give a topological condition for the usual product of two closed operators acting in a Hilbert space to be closed.
A toroidal compactification of the Fermi surface for the discrete Schrödinger operator.
A trace inequality for functions of triangular Hilbert-Schmidt operators
A unified approach to the strong approximation property and the weak bounded approximation property of Banach spaces
We consider convex versions of the strong approximation property and the weak bounded approximation property and develop a unified approach to their treatment introducing the inner and outer Λ-bounded approximation properties for a pair consisting of an operator ideal and a space ideal. We characterize this type of properties in a general setting and, using the isometric DFJP-factorization of operator ideals, provide a range of examples for this characterization, eventually answering a question...
A unitary invariant for pairs of self-adjoint operators.
A universal non-compact operator
A version of the Grothendieck theorem for subspaces of analytic functions in lattices.
A weighted estimate for an intermediate operator on the cone of nonnegative functions.
A Weyl-Titchmarsh type formula for a discrete Schrödinger operator with Wigner-von Neumann potential
We consider a discrete Schrödinger operator 𝒥 with Wigner-von Neumann potential not belonging to l². We find the asymptotics of orthonormal polynomials associated to 𝒥. We prove a Weyl-Titchmarsh type formula, which relates the spectral density of 𝒥 to a coefficient in the asymptotics of the orthonormal polynomials.
A₁-regularity and boundedness of Calderón-Zygmund operators
The Coifman-Fefferman inequality implies quite easily that a Calderón-Zygmund operator T acts boundedly in a Banach lattice X on ℝⁿ if the Hardy-Littlewood maximal operator M is bounded in both X and X'. We establish a converse result under the assumption that X has the Fatou property and X is p-convex and q-concave with some 1 < p, q < ∞: if a linear operator T is bounded in X and T is nondegenerate in a certain sense (for example, if T is a Riesz transform) then M is bounded in both X and...
Abel means of operator-valued processes
Let be a sequence of independent identically distributed random operators on a Banach space. We obtain necessary and sufficient conditions for the Abel means of to belong to Hardy and Lipschitz spaces a.s. We also obtain necessary and sufficient conditions on the Fourier coefficients of random Taylor series with bounded martingale coefficients to belong to Lipschitz and Bergman spaces.
About the adiabatic stability of resonant states
About the class of ordered limited operators
We give a brief survey of recent results of order limited operators related to some properties on Banach lattices.
About the generating function of a left bounded integer-valued random variable
We give a relation between the sign of the mean of an integer-valued, left bounded, random variable and the number of zeros of inside the unit disk, where is the generating function of , under some mild conditions
Abschätzungen für den zweiten Eigenwert eines positiven Operators.
Absence of point spectrum for a class of discrete Schrödinger operators with quasiperiodic potential.
Absence of the singular continuous component in the spectrum of analytic direct integrals.
Absolute and Ordinary Köthe-Toeplitz Duals of Some Sets of Sequences and Matrix Transformations
Absolute continuity and hyponormal operators.
Absolute continuity for Jacobi matrices with power-like weights
This work deals with a class of Jacobi matrices with power-like weights. The main theme is spectral analysis of matrices with zero diagonal and weights where α ∈ (0,1]. Asymptotic formulas for generalized eigenvectors are given and absolute continuity of the matrices considered is proved. The last section is devoted to spectral analysis of Jacobi matrices with qₙ = n + 1 + (-1)ⁿ and .