47A48 Operator colligations (= nodes), vessels, linear systems, characteristic functions, realizations, etc. 435

47A52 Linear operators and ill-posed problems, regularization [See also 35R25, 47J06, 65F22, 65J20, 65L08, 65M30, 65R30] 1083

47A56 Functions whose values are linear operators (operator- and matrix-valued functions, etc., including analytic and meromorphic ones) 2067

47A57 Linear operator methods in interpolation, moment and extension problems [See also 30E05, 42A70, 42A82, 44A60] 1328

47A66 Quasitriangular and nonquasitriangular, quasidiagonal and nonquasidiagonal linear operators 274

47A68 Factorization theory (including Wiener-Hopf and spectral factorizations) of linear operators 1129