Nonlinear operations on a class of modulation spaces

Tomoya Kato, Mitsuru Sugimoto, Naohito Tomita

We discuss when the nonlinear operation $f\mapsto F(f)$ maps the modulation space $M_s^{p,q}({\mathbb{R}}^n)$ ($1\le p,q\le \infty$) to the same space again. It is known that $M^…