Block normal matrices and Gershgorin-type discs
Jakub Kierzkowski, Alicja Smoktunowicz · Electronic Journal of Linear Algebra · 2011
The block analogues of the theorems on inclusion regions for the eigenvalues of normal matrices are given.By an inclusion region for a given matrix A we mean a region of the complex plane that contains at least one of the eigenvalues of A. Some nonsingularity results for partitioned matrices are also presented.