Perturbation Theory for Linear Operators
by Tosio Kato · Springer (Classics in Mathematics)
Kato's reference monograph on linear operators in finite-dimensional, Banach and Hilbert spaces. Covers closed and closable operators, adjoints, resolvents, analytic and asymptotic perturbation of eigenvalues, sectorial forms, semigroups and scattering theory. Capstone reference; the only one treating closed operators in Banach spaces and eigenvalue perturbation this exhaustively.
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