# Category:Operator theory

Here is a list of articles in the Operator theory category of the Computing portal that unifies foundations of mathematics and computations using computers.
**Operator theory** is the branch of functional analysis which deals with bounded linear operators and their properties. It can be split crudely into two branches, although there is considerable overlap and interplay between them. These extend the spectral theory, for bounded operators.

## Subcategories

This category has the following 7 subcategories, out of 7 total.

### D

### F

### I

### L

### S

### U

## Pages in category "Operator theory"

The following 139 pages are in this category, out of 139 total.

- Operator theory
*(computing)*

### A

- Abstract index group
*(computing)* - Affiliated operator
*(computing)* - Antieigenvalue theory
*(computing)* - Approximation property
*(computing)* - AW*-algebra
*(computing)*

### B

- Banach–Stone theorem
*(computing)* - Beltrami equation
*(computing)* - Berezin transform
*(computing)* - Bergman space
*(computing)* - Bounded inverse theorem
*(computing)* - Bounded operator
*(computing)* - Browder–Minty theorem
*(computing)*

### C

- Calderón projector
*(computing)* - Calkin algebra
*(computing)* - Cauchy–Schwarz inequality
*(computing)* - Choi's theorem on completely positive maps
*(computing)* - Cholesky decomposition
*(computing)* - Commutant lifting theorem
*(computing)* - Compact operator
*(computing)* - Compact operator on Hilbert space
*(computing)* - Composition operator
*(computing)* - Contraction (operator theory)
*(computing)* - Controlled invariant subspace
*(computing)* - Convexoid operator
*(computing)* - Cotlar–Stein lemma
*(computing)* - Crossed product
*(computing)* - Cyclic and separating vector
*(computing)*

### D

- De Branges space
*(computing)* - Densely defined operator
*(computing)* - Differential operator
*(computing)* - Dilation (operator theory)
*(computing)* - Discrete Laplace operator
*(computing)* - Dissipative operator
*(computing)* - Dixmier trace
*(computing)* - Douglas' lemma
*(computing)*

### E

- Eigenvalues and eigenvectors of the second derivative
*(computing)* - Extensions of symmetric operators
*(computing)*

### F

- Farrell–Markushevich theorem
*(computing)* - Finite-rank operator
*(computing)* - Friedrichs extension
*(computing)* - Fuglede's theorem
*(computing)*

### G

- Gelfand–Naimark theorem
*(computing)* - Grunsky matrix
*(computing)*

### H

- Hamiltonian (quantum mechanics)
*(physics)* - Hardy space
*(computing)* - Hermitian adjoint
*(computing)* - Hilbert C*-module
*(physics)* - Hilbert space
*(computing)* - Hilbert–Schmidt integral operator
*(computing)* - Hilbert–Schmidt operator
*(computing)* - Hilbert–Schmidt theorem
*(computing)* - Hypercyclic operator
*(computing)* - Hyponormal operator
*(computing)*

### I

- Indefinite inner product space
*(computing)* - Index group
*(computing)* - Integration by parts operator
*(computing)* - International Workshop on Operator Theory and its Applications
*(computing)* - Invariant subspace
*(computing)* - Invariant subspace problem
*(computing)*

### J

- Jacobi operator
*(computing)* - Jordan operator algebra
*(computing)*

### K

- Kato's conjecture
*(computing)* - Kronecker sum of discrete Laplacians
*(computing)* - Krylov subspace
*(computing)* - Kuiper's theorem
*(computing)*

### L

- Limiting absorption principle
*(physics)* - Linear subspace
*(computing)* - Liouville space
*(computing)* - Littlewood subordination theorem
*(computing)*

### M

- Min-max theorem
*(computing)* - Multipliers and centralizers (Banach spaces)
*(computing)*

### N

- Naimark's dilation theorem
*(computing)* - Nemytskii operator
*(computing)* - Nest algebra
*(computing)* - Neumann–Poincaré operator
*(computing)* - Nilpotent operator
*(computing)* - Normal operator
*(computing)* - Nuclear operators between Banach spaces
*(computing)* - Nuclear space
*(computing)* - Numerical range
*(computing)*

### O

- Operator
*(physics)* - Operator algebra
*(computing)* - Operator monotone function
*(computing)* - Operator norm
*(computing)* - Operator space
*(computing)* - Operator system
*(computing)* - Ornstein–Uhlenbeck operator
*(computing)* - Oscillator representation
*(computing)*

### P

- Paranormal operator
*(computing)* - Partial isometry
*(computing)* - Polar decomposition
*(computing)* - Positive-definite kernel
*(computing)* - Positive-definite function on a group
*(computing)* - Product numerical range
*(physics)* - Pseudo-monotone operator
*(computing)*

### Q

- Quasinormal operator
*(computing)*

### R

- Real rank (C*-algebras)
*(computing)* - Reflexive operator algebra
*(computing)* - Resolvent set
*(computing)* - Riesz–Thorin theorem
*(computing)*

### S

- Schatten class operator
*(computing)* - Schatten norm
*(computing)* - Sedrakyan's inequality
*(computing)* - Self-adjoint operator
*(computing)* - Sherman–Takeda theorem
*(computing)* - Singular integral operators of convolution type
*(computing)* - Singular integral operators on closed curves
*(computing)* - Singular value
*(computing)* - Sobolev spaces for planar domains
*(computing)* - Spectral theory of ordinary differential equations
*(computing)* - Stein–Strömberg theorem
*(computing)* - Stinespring factorization theorem
*(computing)* - Strictly singular operator
*(computing)* - Sturm-Liouville theory
*(computing)* - Sturm–Liouville theory
*(computing)* - Subfactor
*(computing)* - Subnormal operator
*(computing)* - Symmetric operator
*(computing)* - Symmetrizable compact operator
*(computing)* - Sz.-Nagy's dilation theorem
*(computing)*

### T

- Toeplitz operator
*(computing)* - Tomita–Takesaki theory
*(computing)* - Topological tensor product
*(computing)* - Trace class
*(computing)* - Trace inequality
*(computing)* - Transfer operator
*(computing)* - Tree kernel
*(computing)*

### U

- Unbounded operator
*(computing)* - Uniformly bounded representation
*(computing)* - Unitary operator
*(computing)*

### V

- Volterra operator
*(computing)* - Von Neumann algebra
*(computing)* - Von Neumann bicommutant theorem
*(computing)* - Von Neumann's inequality
*(computing)* - Von Neumann's theorem
*(computing)*

### W

- Weyl–von Neumann theorem
*(computing)* - Wold's decomposition
*(computing)* - Workshop on Numerical Ranges and Numerical Radii
*(computing)*