Existence and multiplicity of periodic solution for non-autonomous second-order systems with linear nonlinearity

摘要

The purpose of this paper is to study the existence and multiplicity of periodic solution for the following non-autonomous second-order systems:{u(0) - u(T) = <(u)over dot>(0) - <(u)over dot>(T) = 0.<(u)double over dot>(t) = delF(t, u(t)) a.e. t is an element of [0, T],Some new existence and multiplicity theorems are obtained by using the least action principle and the minimax method. (C) 2004 Elsevier Ltd. All rights reserved.