Divisors of Polynomial Matrices: Theory and Applications

In this paper divisors G(s) of a given polynomial matrix N(s) are discussed. The paper deals with the following problems: extraction of a greatest right (left) divisor of N(s), computation for a given state-space system (C, A, B) a state-space feedback making the system (C, A + BF, B) maximally or appropriately unobservable and determination for a given system (C. A, B, O, W, O) a disturbance rejection feedback F. The developed methods are very simple from computational point of view and can be easily implemented in the software via existing computer library procedures.