Functions operating on modulation spaces and nonlinear dispersive equations

Divyang G. Bhimani, P. K. Ratnakumar

The aim of this paper is two fold. We show that if a complex function $F$ on $\C$ operates in the modulation spaces $M^{p,1}({\mathbb{R}}^n)$ by composition, then $F$ is real analytic on $\R…