Long-time asymptotics for the nonlocal Kundu–nonlinear-Schrödinger equation by the nonlinear steepest descent method

We study the long-time asymptotics of the nonlocal Kundu–nonlinear-Schrödinger equation with a decaying initial value. The long-time asymptotics of the solution follow from the nonlinear steepest descent method proposed by Deift–Zhou and the Riemann–Hilbert method.