On the robust stability of discrete-time systems

A sufficient stability condition for monic Schur polynomials is obtained via, so-called, reflection coefficients of polynomials and the discrete version of Kharitonov´s weak theorem. The discrete Kharitonov theorem defines only (n-1)-dimensional stable hyperrectangle for n-degree monic polynomials. By the use of a linear Schur invariant transformation we put stable line segments through vertices of this hyperrectangle and find an n-dimensional stable polytope with all vertices on the stability boundary