I. Introduction
Global convergence of recurrent neural networks is an important dynamic property of neural networks for certain applications, including those relating to optimization. The global convergence of neural networks has been widely studied in recent years. One main goal of global convergence analysis is to establish weak and simple conditions which can be verified to guarantee the global convergence of networks. Since many neural networks are described in terms of nonlinear differential systems, necessary and sufficient conditions are difficult to derive. Recently, many sufficient conditions of global convergence for recurrent neural networks have been reported.