Widths and entropy numbers of embeddings of Sobolev classes on a Hölder domain

In the present paper we improve Besov’s recent result about upper estimates for the entropy numbers of Sobolev classes on a Hölder domain (in the case when the definition of the Sobolev class involves all partial derivatives of order $r$). We also obtain upper estimates for the Kolmogorov, linear and the Gelfand widths.