“…e second natural way of dealing with this problem, which is the framework of this paper, is straightly related to the coupled partial differential equations (see [1,8,9]). e aim of this paper is to generalize the existence of strong solutions of the problem introduced in [1,8,9]. More precisely, we will give new results about the existence of strong solutions, in particular, without assuming that ‖Ψ‖ H 2 is small (as in [8], eorem 4).…”