Computable stability criterion of linear neutral systems with unstable difference operators

This paper is concerned with linear neutral systems with unstable difference operators. All the unstable characteristic roots of the linear neutral systems are located in a bounded half circular region. Then, based on the argument principle, a computable stability criterion is derived which is necessary and sufficient for asymptotic stability of the neutral systems. Furthermore, the number of the unstable characteristic roots is given. The main results of the present paper extend those in literature. Numerical experiments are provided to illustrate the main results.