  In this paper we prove the non-linear stability of a system of non-linear
wave equations satisfying the weak null condition. In particular, this includes
the case of the non-linear stability of Minkowski spacetime times a $d$-torus
subject to perturbations depending only on the non-compact coordinates. Our
argument very closely follows the proof of the non-linear stability of
Minkowski spacetime in [Lindblad-Rodnianski-2010].
