Periodic solution for a class of higher-dimension impulsive functional differential equations with parameter

In this paper, by employing a fixed-point theorem in cones, we study a kind of higher-dimension impulsive functional differential equation with parameter as follows: x´ = A(t)x(t) + lambdaf(t, x_t), t npar tau_k, Deltax|_{t = tau k} = I_k(x(tau_k)), t = tau_k, k isin Z₊. some results on the existence of periodic solutions are obtained.