Spaces of Besov-Sobolev type and a problem on nonlinear approximation

Óscar Domínguez, Andreas Seeger, Brian Street +2

We study fractional variants of the quasi-norms introduced by Brezis, Van Schaftingen, and Yung in the study of the Sobolev space ${\dot{W}}^{1,p}$. The resulting spaces are identifie…