On uniqueness of solutions to the surface electromigration equation

In this paper we investigate on uniqueness properties of solutions to the surface electromigration (SEM) equation, which is a generalisation of the more classical Zakharov-Kuznetsov equation of plasma physics with non-local perturbation terms. We will show that if the difference of two solutions has a sufficiently strong spatial decay at two different instants of time, then the two solutions coincide on the whole interval of time.