A type nonlinear differential difference system ·↑x(i)(t)=n↑∑↑j=1[αijfij(xj(t))+bijgij(xj(t-τj))](i=1,2,…,n) is studied.We give some theorems which
<正>Hurewicz-Radon theorem [1] gives a sufficient and necessary condition about the existence of an orthogonal multiplication f:Rk×Rn→Rn. In this paper,we