Scalar
one-dimensional parabolic equations with
periodically
time-dependent nonlinearities are considered. For each such equation,
the associated discrete-time dynamical system is shown to admit
Morse
decompositions of the global attractor whose Morse sets are contained
in a given, arbitrarily small neighborhood
of the set of fixed points.
Existence of such Morse decompositions implies that the chainrecurrent
set coincides with the set of fixed points. In particular,
the dynamical
system has a gradient-like structure. As an application of
these results,
a description of the asymptotic behavior
of solutions of asymptotically
periodic equations is given: any bounded solution approaches
a set of
periodic solutions of the limiting equation. Other
possible applications to
nonlocal equations and thin domain problems are discussed.