Non-self-adjoint Differential Operators
نویسنده
چکیده
We describe methods which have been used to analyze the spectrum of non-self-adjoint differential operators, emphasizing the differences from the self-adjoint theory. We find that even in cases in which the eigenfunctions can be determined explicitly, they often do not form a basis; this is closely related to a high degree of instability of the eigenvalues under small perturbations of the operator. AMS subject classifications:34L05, 35P05, 47A10, 47A12 keywords: spectrum, eigenvalue, resolvent, differential operator, non-selfadjoint operator, pseudospectra, asymptotics
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