May 2013, volume 223, number 1051 (fifth of 5 numbers).

This monograph presents a comprehensive treatment of second order divergence form elliptic operators with bounded measurable $t$-independent coefficients in spaces of fractional smoothness, in Besov and weighted $L^p$ classes. The authors establish: (1) Mapping properties for the double and single layer potentials, as well as the Newton potential (2) Extrapolation-type solvability results: the fact that solvability of the Dirichlet or Neumann boundary value problem at any given $L^p$ space automatically assures their solvability in an extended range of Besov spaces (3) Well-posedness for...