“…In recent years, the invariant and attracting sets of dynamical systems have attracted considerable attention, and various interesting results on this problem have been reported (Sawano 1980, Marion 1987, GyoÈ ri 1990, Xiang 1991, Xu 1996, Hale 1997, Razgulin 1997). However, not much has been developed in the direction of the Hop® eld neural networks system.…”