Perturbations of Eigenvalues of Non-normal Matrices The problem considered is to give bounds for finite perturbations of simple and multiple eigenvalues of nonnormal matrices, where these bounds are in terms of the eigenvalues, the departure from normality, and the Frobenius norm of the perturbation matrix, but not in terms of the eigen system. The bounds which are derived are shown to be almost attainable for any set of matrices. CACM January, 1975 van der Sluis, A. perturbation of eigenvalues, non-normal matrices, departure from normality, Gershgorin circles 5.14 CA750106 JB January 12, 1978 10:31 AM 2805 5 2805 2805 5 2805 2805 5 2805