Generalization of a complex system by equivalent transform in the discrete sense

The authors introduce a relation called equivalence in the discrete sense and define a complex system corresponding to a real system with real-axis poles as well as complex conjugate poles that is a generalization of a complex system considered previously by the authors (1990). The introduction of such a complex system makes it more suitable for treating not only the robust control but also pole assignment in the separate regions. It is possible to treat root-clustering problems in three separate regions: in two symmetric regions with respect to the real axis and on a real-axis segment.<>