Abstract.Suppose a given evolutionary equation has a compact attractor and the evolutionary equation is approximated by a finite-dimensional system. Conditions are given to ensure the approximate system has a compact attractor which converges to the original one as the approximation is refined. Applications are given to parabolic and hyperbolic partial differential equations.
Introduction.Suppose A" is a Banach space and T(t), t > 0, is a Crsemigroup on X with r > 0; that is, T(t), t > 0, is a semigroup with T(t) continuous in t, x together with the derivatives in x up through the order r.Following standard terminology (see, for instance, Hale [12]), a set B C X is said to attract a set C C X under the semigroup T(t) if, for any e > 0, there is a t0 = t0(B,C,e) such that T(t)C C M(B,e) for t > t0, where M(B,e) denotes the