1. It was proved by Frobenius [l] that any function f(A, B) of two commutative «X« square matrices A, B has as characteristic roots the numbers /(X¿, Hi) where X¿ are the characteristic roots of A and pi the characteristic roots of B, both taken in a special ordering independent of the function /. However, commutativity of A and B is known not to be a necessary condition [2]. Matrices which hav...