Electronic Journal of Differential Equations,
Vol. 2009(2009), No. 97, pp. 1-5.

Title: Uniform boundedness of solutions for a class of
       Lienard equations

Authors: Guo-Rong Ye  (Jiangxi Normal Univ. Nanchang, China)
         Hui-Sheng Ding (Jiangxi Normal Univ. Nanchang, China)
	 Xi-Lang Wu   (Jiangxi Normal Univ. Nanchang, China)

Abstract:
 In this article, we study a class of  Lienard equations
 $$
 x''(t)+f(x(t))x'(t)+g_1(x(t))+g_2(x(t-\tau(t))=e(t).
 $$
 Under some suitable conditions, we ensure that all solutions
 of the above Lienard equations are uniformly bounded.
 Our assumptions are less restrictive than those in [9];
 thus we extend some previous results.

Submitted December 2, 2008. Published August 11, 2009.
Math Subject Classifications: 35R10, 47D09.
Key Words: Second order differential equations; 
           cosine function of operators; abstract Cauchy problem.