On indecomposable normal matrices in spaces with indefinite scalar product
arXiv:math/0512585 · doi:10.1016/S0024-3795(96)00247-9
Abstract
Finite dimensional linear spaces (both complex and real) with indefinite scalar product [.,.] are considered. Upper and lower bounds are given for the size of an indecomposable matrix that is normal with respect to this scalar product in terms of specific functions of v = min{v-, v+}, where v-, (v+) is the number of negative (positive) squares of the form [x,x]. All the bounds except for one are proved to be strict.
9 pages