“…This solution is based on the proper adaptation of the finite-gap method [32,48,53,56,62,66] (see [52] for its first application to NLS) to it. See also [39] for an alternative approach to the study of the AW recurrence, based on matched asymptotic expansions; see [41] for the analytic study of the phase resonances in the AW recurrence; see [30,31,72] for the analytic study of the AW recurrence in other NLS type models: respectively the PT-symmetric NLS equation [5], the Ablowitz-Ladik model [4], and the massive Thirring model [63,77], see [29,73] for the study of the stabilisation effects of higher-order corrections to NLS. The fundamental matrix solution T(λ, x, y, t) of ( 4)- (6) in the x-periodic problem, such that T(λ, y, y, t) = E, where E is the identity matrix (see [34]), is an entire function of λ.…”