On an elliptic equation arising from composite materials
arXiv:1505.01042 · doi:10.1007/s00205-016-0996-9
Abstract
In this paper, we derive an interior Schauder estimate for the divergence form elliptic equation \begin{equation*} D_i(a(x)D_iu)=D_if_i \end{equation*} in , where and are piecewise Hölder continuous in a domain containing two touching balls as subdomains. When and is piecewise constant, we prove that is piecewise smooth with bounded derivatives. This completely answers a question raised by Li and Vogelius [7] in dimension 2.
36 pages, 2 figures, submitted