Bounded compositions on scaling invariant Besov spaces

Herbert Koch, Pekka Koskela, Eero Saksman +1

For $0<s<1<q<\infty$, we characterize the homeomorphisms $\phi :{\Re }^n\to {\Re }^n$ for which the composition operator $f\mapsto f\circ \phi$ is bounded on the homogeneous, sc…