Pashaev, O.K.; Lee, J.-H.
(Symmetry, Integrability and Geometry: Methods and Applications, 2017)
By the recursion operator of the Kaup-Newell hierarchy we construct the relativistic derivative NLS (RDNLS) equation and the corresponding Lax pair. In the nonrelativistic limit c→∞ it reduces to DNLS equation and preserves ...