BOUNDARY TESTING OF STABILITY FOR THE FAMILY OF NONLINEAR PARAMETRIZED REAL POLYNOMIALS

This paper studies the robust stability of the polynomials which are p arametrized in a nonlinear way by the establishment of the concept of single-directed conditional extreme value. The necessary and sufficien t condition to determine the stability of the family of polynomials by testing the boundary of the parameter domain is presented for the sit uation when the mapping from parameter space to the coefficient space is continuous. Therefore the method of boundary testing used for check ing the stability of linearly parametrized polynomials is generalized to a class of polynomials which satisfies the conditions given in this paper. (C) 1997 by John Wiley & Sons, Ltd.