On perturbations of matrix pencils with real spectra, a revisit
Ren‐Cang Li · Mathematics of Computation · 2002
This paper continues earlier studies by Bhatia and Li on eigenvalue perturbation theory for diagonalizable matrix pencils having real spectra. A unifying framework for creating crucial perturbation equations is developed. With the help of a recent result on generalized commutators involving unitary matrices, new and much sharper bounds are obtained.