Stability of schur polynomials under coefficient perturbation

In this paper, we are concerned with the stability robustness of characteristic polynomials with perturbed coefficients for linear discrete-time systems. An upper bound on the allowable coefficient perturbation of a Schur polynomial with retaining stability is obtained. The proposed upper bound is directly formulated in terms of the polynomial under consideration and its value can be determined by numerical computation. We also provide a sufficient condition for the stability of interval polynomials.