Exponential stability of discrete time uncertain systems with time-varying delay

This paper addresses the exponential stability and estimates the stability degree of discrete systems with a time-varying delay and uncertainties. On the basis of the Lyapunov stability theorem together with the improved Razumikhin type theorem and norm techniques, several new delay-independent criteria are presented to guarantee the exponential stability and to estimate the stability degree of the mentioned systems. Although the Lyapunov stability theorem is utilized, it is not necessary to solve any troublesome or even unsolvable Lyapunov equations. Comparing to existing result, the proposed work is more general.