Type: Article
Publication Date: 2012-12-29
Citations: 42
DOI: https://doi.org/10.2140/apde.2012.5.983
We continue the development, by reduction to a first-order system for the conormal gradient, of L 2 a priori estimates and solvability for boundary value problems of Dirichlet, regularity, Neumann type for divergence-form second-order complex elliptic systems.We work here on the unit ball and more generally its bi-Lipschitz images, assuming a Carleson condition as introduced by Dahlberg which measures the discrepancy of the coefficients to their boundary trace near the boundary.We sharpen our estimates by proving a general result concerning a priori almost everywhere nontangential convergence at the boundary.Also, compactness of the boundary yields more solvability results using Fredholm theory.Comparison between classes of solutions and uniqueness issues are discussed.As a consequence, we are able to solve a long standing regularity problem for real equations, which may not be true on the upper half-space, justifying a posteriori a separate work on bounded domains.Andreas Rosén was formerly called Andreas Axelsson.