The book systematically develops the nonlinear potential theory
connected with the weighted Sobolev spaces, where the weight usually
belongs to Muckenhoupt's class of Ap weights. These spaces occur as
solutions spaces for degenerate elliptic partial differential equations.
The Sobolev space theory covers results concerning approximation,
extension, and interpolation, Sobolev and Poincaré inequalities, Maz'ya
type embedding theorems, and isoperimetric inequalities. In the chapter
devoted to potential theory, several weighted capacities are
investigated. Moreover, "Kellogg lemmas" are established for various
concepts of thinness. Applications of potential theory to weighted
Sobolev spaces include quasi continuity of Sobolev functions, Poincaré
inequalities, and spectral synthesis theorems.