Attractors for a non-autonomous Liénard equation

Abstract

In this paper we prove the existence of pullback and uniform attractors for a non-autonomous Liénard equation. The relation among these attractors is also discussed. After that, we consider that the Liénard equation includes forcing terms which belong to a class of functions extending periodic and almost peri- odic functions recently introduced by Kloeden and Rodrigues in [14]. Finally, we estimate the Hausforff dimension of the pullback attractor. We illustrate these results with a numerical simulation: we present a simulation showing the pullback attractor for the non-autonomous Van der Pol equation, an important special case of the non-autonomous Liénard equation.