Continuity of composition operators in Sobolev spaces

Gérard Bourdaud, Madani Moussai

We prove that all the composition operators $T_f(g):=f\circ g$, which take the Adams-Frazier space $W_p^m\cap {\dot{W}}_{mp}^1({\mathbb{R}}^n)$ to itself, are continuous mapping…