Boundary properties of functions of the Sobolev space defined in a planar domain with angular points (Q1921819)

Let \(G\) be a bounded planar domain with a piecewise smooth boundary having a finite number of angular points which are vertexes of outer and inner corners with respect to the domain. The author gives a reversible characterization of traces of functions from the Sobolev space \(W^l_p(G)\) and their derivatives in non-tangential directions. The characterization is given in terms of weighted Besov-type spaces. The paper is a continuation of the author's research [Sib. Adv. Math. 3, No. 1, 167-199 (1993; Zbl 0849.46026)] and [Sov. Math., Dokl. 44, 96-99 (1992; Zbl 0798.46028)].