Abstract
The present paper is concerned with the robust stability of discrete-time plants when the characteristic matrix is known to be an element of a polytope of matrices. A lower bound of the degree of stability is presented which has a close parallelism to the continuous-time case. That is, the lower bound is expressed as the value of a two-person zero-sum game. Further the optimal solution provides a Lyapunov function common to all the elements of the polytope. Application to stability analysis of uncertain large-scale systems is discussed.
