Our aim in this note is to construct attractors and exponential attractors
for a general class of nonautonomous semilinear wave equations. Following t
he approach described in [1], we define a semigroup S(t) associated to an a
utonomous system, and then prove, using an energy functional, that S(t) is
an a-contraction and satisfies the squeezing property. (C) 2000 Elsevier Sc
ience Ltd. All rights reserved.