About one high-order linear equation of mixed type.
About some linear operators.
A-Browder-type theorems for direct sums of operators
We study the stability of a-Browder-type theorems for orthogonal direct sums of operators. We give counterexamples which show that in general the properties , , and are not preserved under direct sums of operators. However, we prove that if and are bounded linear operators acting on Banach spaces and having the property , then has the property if and only if , where is the upper semi-B-Weyl spectrum of . We obtain analogous preservation results for the properties , and with...
Abschätzungen für den zweiten Eigenwert eines positiven Operators.
Absence of eigenvalues for integro-differential operators with periodic coefficients.
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 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 .
Absolutely continuous and singular spectral shift functions [Book]
Absolutely--summing operators in -spaces I
Absolutely--summing operators in -spaces II
Absolutely P-Summing, P-Nuclear Operators and Their Conjugates.
Absolutely Summing Terraced Matrices
Let α > 0. By Cα we mean the terraced matrix defined by [...] if 1 ≤ k ≤ n and 0 if k > n. In this paper, we show that a necessary and sufficient condition for the induced operator on lp, to be p-summing, is α > 1; 1 ≤ p < ∞. When the more general terraced matrix B, defined by bnk = βn if 1 ≤ k ≤ n and 0 if k > n, is considered, the necessary and sufficient condition turns out to be [...] in the region 1/p + 1/q ≤ 1.
Absorbers: Definitions, properties and applications.
Abstract Weyl-type theorems
In this paper, we give a new approach to the study of Weyl-type theorems. Precisely, we introduce the concepts of spectral valued and spectral partitioning functions. Using two natural order relations on the set of spectral valued functions, we reduce the question of relationship between Weyl-type theorems to the study of the set difference between the parts of the spectrum that are involved. This study solves completely the question of relationship between two spectral valued functions, comparable...
Accelerated Landweber iterations for the solution of ill-posed equations.
Accretive approximation in C*-algebras
The problem of approximation by accretive elements in a unital C*-algebra suggested by P. R. Halmos is substantially solved. The key idea is the observation that accretive approximation can be regarded as a combination of positive and self-adjoint approximation. The approximation results are proved both in the C*-norm and in another, topologically equivalent norm.
Accurate asymptotic formulas for eigenvalues and eigenfunctions of a boundary-value problem of fourth order.
Accurate eigenvalue asymptotics for the magnetic Neumann Laplacian
Motivated by the theory of superconductivity and more precisely by the problem of the onset of superconductivity in dimension two, many papers devoted to the analysis in a semi-classical regime of the lowest eigenvalue of the Schrödinger operator with magnetic field have appeared recently. Here we would like to mention the works by Bernoff-Sternberg, Lu-Pan, Del Pino-Felmer-Sternberg and Helffer-Morame and also Bauman-Phillips-Tang for the case of a disc. In the present paper we settle one important...