High order multiscale analysis of discrete integrable equations

In this article we present the results obtained applying the multiple scale expansion up to the order ε⁶ to a dispersive multilinear class of equations on a square lattice depending on 13 parameters. We show that the integrability conditions given by the multiple scale expansion give rise to 4 nonlinear equations, 3 of which seem to be new, depending at most on 2 parameters.