Some general theorems on iterants
Paul R. Stein · Journal of research of the National Bureau of Standards · 1952
If B is a s quare matrix , then it is known that a necessary and sufficie nt condition that lim Bn=O, is that t he characteristic roots of B are all of modulus less than unity.An altern a-n~co J tive condition is given in t his paper, in terms of Hermitian matrices.Further, a generalizat ion of the result is obtained that covers cases of matrices B whe t her B n does or does not converge to 0, exce pt for very special matrices .