47XX 


Operator theory 

47Axx 

General theory of linear operators 


47A05 
General (adjoints, conjugates, products, inverses, domains, ranges, etc.) 


47A06 
Linear relations (multivalued linear operators) 


47A07 
Forms (bilinear, sesquilinear, multilinear) 


47A10 
Spectrum, resolvent 


47A11 
Local spectral properties 


47A12 
Numerical range, numerical radius 


47A13 
Severalvariable operator theory (spectral, Fredholm, etc.) 


47A15 
Invariant subspaces 


47A16 
Cyclic and hypercyclic vectors 


47A20 
Dilations, extensions, compressions 


47A25 
Spectral sets 


47A30 
Norms (inequalities, more than one norm, etc.) 


47A35 
Ergodic theory [See also 28Dxx, 37Axx] 


47A40 
Scattering theory [See also 34L25, 35P25, 81Uxx] 


47A45 
Canonical models for contractions and nonselfadjoint operators 


47A46 
Chains (nests) of projections or of invariant subspaces, integrals along chains, etc. 


47A48 
Operator colligations (= nodes), vessels, linear systems, characteristic functions, realizations, etc. 


47A50 
Equations and inequalities involving linear operators, with vector unknowns 


47A52 
Illposed problems, regularization 


47A53 
(Semi) Fredholm operators; index theories [See also 58B15, 58J20] 


47A55 
Perturbation theory 


47A56 
Functions whose values are linear operators (operator and matrix valued functions, etc., including analytic and meromorphic ones) 


47A57 
Operator methods in interpolation, moment and extension problems [See also 30E05, 42A70, 42A82, 44A60] 


47A58 
Operator approximation theory 


47A60 
Functional calculus 


47A62 
Equations involving linear operators, with operator unknowns 


47A63 
Operator inequalities 


47A64 
Operator means, shorted operators, etc. 


47A65 
Structure theory 


47A66 
Quasitriangular and nonquasitriangular, quasidiagonal and nonquasidiagonal operators 


47A67 
Representation theory 


47A68 
Factorization theory (including WienerHopf and spectral factorizations) 


47A70 
(Generalized) eigenfunction expansions; rigged Hilbert spaces 


47A75 
Eigenvalue problems [See also 49R50] 


47A80 
Tensor products of operators [See also 46M05] 


47A99 
None of the above, but in this section 