Some Remarks Concerning the Real and Imaginary Parts of the Characteristic Roots of a Finite Matrix
Daniel C. Lewis, Olga Taussky · Journal of Mathematical Physics · 1960
Some theorems are obtained on the existence of certain determinantal equations whose roots are separately the real or imaginary parts of the characteristic roots of a given matrix with simple elementary divisors. When the elementary divisors are not simple, similar, but somewhat less precise, results are obtained.