47Axx General theory of linear operators

47A05  General (adjoints, conjugates, products, inverses, domains,
               ranges, etc.)
47A10  Spectrum, resolvent
47A11  Local spectral properties
47A12  Numerical range
47A13  Several-variable spectral theory
47A15  Invariant subspaces
47A20  Dilations, extensions, compressions
47A25  Spectral sets
47A30  Norms (inequalities, more than one norm, etc.)
47A35  Ergodic theory, See also {28Dxx}
47A40  Scattering theory, See also {34L25, 35P25, 81Uxx}
47A45  Canonical models for contractions and nonselfadjoint
               operators
47A48  Operator colligations (= nodes)
47A50  Equations and inequalities involving linear operators, with
               vector unknowns
47A53  (Semi-) Fredholm operators; index theories, See Also {
               58B10, 58G12}
47A55  Perturbation theory
47A56  Functions whose values are linear operators (operator and
               matrix pencils, etc.)
47A57  Operator methods in interpolation, moment and extension
               problems, See also {30E05, 42A70, 42A82}
47A58  Operator approximation theory
47A60  Functional calculus
47A62  Equations involving linear operators, with operator
               unknowns
47A63  Operator inequalities, operator means, shorted operators,
               etc.
47A65  Structure theory
47A66  (Non)quasitriangular, (non)quasidiagonal operators
47A67  Representation theory
47A68  Factorization theory (including Wiener-Hopf and spectral
               factorizations)
47A70  (Generalized) eigenfunction expansions; rigged Hilbert
               spaces
47A75  Eigenvalue problems, See also {49Rxx}
47A80  Tensor products of operators, See also {46M05}
47A99  None of the above but in this section