摘要
This letter presents a new Razumikhin-type condition. If P(V(x(ξ)))≥ V(x(t)), then we consider (?) (this has not been known so far) and establish two theorems to determine the instability of functional differential equations at (?) within the range of V>0 under the condition of P(V(x(ξ)))≥ V(x(ξ)) ≤ V(x(t)).
