Remarks on Sobolev–Morrey–Campanato spaces defined on $C^{0,\gamma}$ domains

We discuss a few old results concerning embedding theorems for Campanato and Sobolev–Morrey spaces adapting the formulations to the case of domains of class $C^{0,\gamma}$, and we present more recent results concerning the extension of functions from Sobolev–Morrey spaces defined on those domains. As a corollary of the extension theorem we obtain an embedding theorem for Sobolev–Morrey spaces on arbitrary $C^{0,\gamma}$ domains.