Periodic solutions to non-autonomous second-order systems Haiyan Wang

摘要

We establish the existence of periodic solution of a class of non-autonomous second-ordersystems, X+μx+V (t, x) = 0, where V (t, x) = (v_1(t, x), ... , v_n(t, x)), if lim_(|x|→∞)v_i(t,x)/|x|=0, i = 1, ... , n, uniformly in t and V is bounded below or above for appropriate rangesof μ.