Elliptic Boundary Value Problems of Second Order in Piecewise Smooth Domains

The book contains a systematic treatment of the qualitative theory of elliptic boundary value problems for linear and quasilinear second order equations in non-smooth domains. The authors concentrate on the following fundamental results: sharp estimates for strong and weak solutions, solvability of the boundary value problems, regularity assertions for solutions near singular points. The book contains the Hardy Friedrichs Wirtinger type inequalities as well as new integral inequalities related to the Cauchy problem for a differential equation. It covers the precise exponents of the solution decreasing rate near boundary singular points and best possible conditions for this. It answers the question about the influence of the coefficients smoothness on the regularity of solutions. It has new existence theorems for the Dirichlet problem for linear and quasilinear equations in domains with conical points. It covers: the precise power modulus of continuity at singular boundary point for solutions of the Dirichlet, mixed and the Robin problems; the behaviour of weak solutions near conical point for the Dirichlet problem for m Laplacian; the behaviour of weak solutions near a boundary edge for the Dirichlet and mixed problem for elliptic quasilinear equations with triple degeneration; and, the behaviour of weak solutions near a boundary edge for the Dirichlet and mixed problem for elliptic quasilinear equations with triple degeneration.