“…On the other hand, there is tremendous ongoing interest to use modulation spaces M p,q (R d ) (see Definition 2.1 below) as a regularity class for the Cauchy data for nonlinear dispersive equations, see e.g., [1,2,31,4,8,3,5,43]. Wang-Zhao-Guo [1] proved local well-posedness for nonlinear Schrödinger equations (NLS) and Navier-Stokes equations in M 2,1 (R d ).…”