Titlebook: Topics in Operator Theory; Constantin Apostol M I. Gohberg (Raymond and Beverly Sackler Faculty of Book 1988 Springer Basel AG 1988 analysi

GNAW

A Note on the Algebra Generated by a Subnormal Operator,f on A can be represented as.where x and y are vectors in H and (·,·) denotes the scalar product in H. We say that A has property (/A.(r)) if, in addition, given s>r and f, we can choose x and y satisfying (1) and..

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精密

On the Four Block Problem, I,esses a number of interesting mathematical properties. The study of this operator will be shown to be reducible to a skew Toeplitz operator problem of the kind studied in [1]. The main theoretical fact proven here is an explicit closed form formula for the essential norm of the four block operator (

Ferritin

Variation of the Point Spectrum under Compact Perturbations,plex plane such that for some compact operator K, Σ is the point spectrum of T - K and Ξ is the point spectrum of its adjoint. The result is applied to study the continuity properties of the function T → σ. (T)., and several related spectral functions.

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Bimodules of Nest Subalgebras of von Neumann Algebras,s work accomplished earlier by Erdos and Power for the case in which the factor is .(.). In the general case many more such bimodules exist than are given by a straightforward extension of the .(.) theory. New techniques are developed for this, including use of a partial coordinate system for bimodu

podiatrist

Stability of Invariant Lagrangian Subspaces I,ons of the matrix or the operator, attracted much attention (see [BGK, GR, GLR1, AFS]). The main motivation to consider these problems comes from factorizations of matrix and operator functions, where invariant subspaces appear as the main tool in describing the factorizations (for this approach to