Abstract. We consider the following nonperiodic diffusion systems Gv(t, x, u, v), Gu(t, x, u, v),whereSuppose that the potential V is positive constant and G(t, x, z) is superquadratic in z as |z| → ∞. By applying a generalized linking theorem for strongly indefinite functionals, we obtain homoclinic solutions z satisfying z(t, x) → 0 as |(t, x)| → ∞.
Mathematics Subject Classification (2000). 58E50 (Variational problems in infinite-dimensional spaces, Applications).