Reducibility of Klein-Gordon equations with maximal order perturbations

Massimiliano Berti, Roberto Feola, Michela Procesi +1

We prove that all the solutions of a quasi-periodically forced linear Klein-Gordon equation ${\psi }_{tt}-{\psi }_{xx}+\mathtt{m}\psi +Q(\omega t)\psi =0$ where $ Q(ωt) := a^{(2)}(ωt, x) \partial_{xx} + a^…