“…Now, we will prove that there exists an inertial manifold M (see a definition in Ref. [7]) for the semigroup S * (t) in the phase space Y = R 2 ×Ḣ 1 per (0, 1)×L 2 per (0, 1), i.e., a submanifold of Y such that (i)S * (t)M ⊂ M for every t ≥ 0, (ii) there exists δ > 0 satisfying that for every bounded set B ⊂ Y, there exists C(B) ≥ 0 such that dist(S(t), M) ≤ C(B)e −δt , t ≥ 0 see, for example, [7] and [23].…”