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Operator norm

About: Operator norm is a research topic. Over the lifetime, 5702 publications have been published within this topic receiving 120300 citations. The topic is also known as: bounded linear operator.

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TL;DR: Dunford and Schwartz as discussed by the authors provided a comprehensive survey of the general theory of linear operations, together with applications to the diverse fields of more classical analysis, and emphasized the significance of the relationships between the abstract theory and its applications.
Abstract: This classic text, written by two notable mathematicians, constitutes a comprehensive survey of the general theory of linear operations, together with applications to the diverse fields of more classical analysis. Dunford and Schwartz emphasize the significance of the relationships between the abstract theory and its applications. This text has been written for the student as well as for the mathematician—treatment is relatively self-contained. This is a paperback edition of the original work, unabridged, in three volumes.

2,890 citations

01 Jan 1967

1,863 citations

01 Jan 1995
TL;DR: In this paper, the authors provide global and asymptotic estimates for the eigenvalues of - + q when q is real and for -+ q when 1 is complete.
Abstract: Linear operations in Banach spaces Entropy numbers, s-numbers, and eigenvalues Unbounded linear operators Sesquilinear forms in Hilbert spaces Sobolev spaces Generalized Dirichlet and Neumann boundary-value problems Second-order differential operators on arbitrary open sets Capacity and compactness criteria Essential spectra Essential spectra of general second-order differential operators Global and asymptotic estimates for the eigen-values of - + q when q is real. Estimates for the singular values of - + q when 1 is complete Bibliography Notation index Subject index

1,792 citations

25 Apr 1985

1,599 citations

05 May 1980
TL;DR: The spectral theory of self-adjoint and normal operators on L2(a, b) spaces has been studied in this article, where it has been shown that the existence and completeness of wave operators can be proved.
Abstract: 1 Vector spaces with a scalar product, pre-Hilbert spaces.- 1.1 Sesquilinear forms.- 1.2 Scalar products and norms.- 2 Hilbert spaces.- 2.1 Convergence and completeness.- 2.2 Topological notions.- 3 Orthogonality.- 3.1 The projection theorem.- 3.2 Orthonormal systems and orthonormal bases.- 3.3 Existence of orthonormal bases, dimension of a Hilbert space.- 3.4 Tensor products of Hilbert spaces.- 4 Linear operators and their adjoints.- 4.1 Basic notions.- 4.2 Bounded linear operators and functionals.- 4.3 Isomorphisms, completion.- 4.4 Adjoint operator.- 4.5 The theorem of Banach-Steinhaus, strong and weak convergence.- 4.6 Orthogonal projections, isometric and unitary operators.- 5 Closed linear operators.- 5.1 Closed and closable operators, the closed graph theorem.- 5.2 The fundamentals of spectral theory.- 5.3 Symmetric and self-adjoint operators.- 5.4 Self-adjoint extensions of symmetric operators.- 5.5 Operators defined by sesquilinear forms (Friedrichs' extension).- 5.6 Normal operators.- 6 Special classes of linear operators.- 6.1 Finite rank and compact operators.- 6.2 Hilbert-Schmidt operators and Carleman operators.- 6.3 Matrix operators and integral operators.- 6.4 Differential operators on L2(a, b) with constant coefficients.- 7 The spectral theory of self-adjoint and normal operators.- 7.1 The spectral theorem for compact operators, the spaces Bp (H1H2).- 7.2 Integration with respect to a spectral family.- 7.3 The spectral theorem for self-adjoint operators.- 7.4 Spectra of self-adjoint operators.- 7.5 The spectral theorem for normal operators.- 7.6 One-parameter unitary groups.- 8 Self-adjoint extensions of symmetric operators.- 8.1 Defect indices and Cayley transforms.- 8.2 Construction of self-adjoint extensions.- 8.3 Spectra of self-adjoint extensions of a symmetric operator.- 8.4 Second order ordinary differential operators.- 8.5 Analytic vectors and tensor products of self-adjoint operators.- 9 Perturbation theory for self-adjoint operators.- 9.1 Relatively bounded perturbations.- 9.2 Relatively compact perturbations and the essential spectrum.- 9.3 Strong resolvent convergence.- 10 Differential operators on L2(?m).- 10.1 The Fourier transformation on L2(?m).- 10.2 Sobolev spaces and differential operators on L2(?m) with constant coefficients.- 10.3 Relatively bounded and relatively compact perturbations.- 10.4 Essentially self-adjoint Schrodinger operators.- 10.5 Spectra of Schrodinger operators.- 10.6 Dirac operators.- 11 Scattering theory.- 11.1 Wave operators.- 11.2 The existence and completeness of wave operators.- 11.3 Applications to differential operators on L2(?m).- A.1 Definition of the integral.- A.2 Limit theorems.- A.3 Measurable functions and sets.- A.4 The Fubini-Tonelli theorem.- A.5 The Radon-Nikodym theorem.- References.- Index of symbols.- Author and subject index.

1,346 citations

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