μ-Values and Spectral Value Sets for Linear Perturbation Classes Defined by a Scalar Product
Michael Karow · SIAM Journal on Matrix Analysis and Applications · 2011
We study the variation of the spectrum of matrices under perturbations which are self- or skew-adjoint with respect to a scalar product. Computable formulas are given for the associated [Formula: see text]-values. The results can be used to calculate spectral value sets for the perturbation classes under consideration. We discuss the special case of complex Hamiltonian perturbations of a Hamiltonian matrix in detail.