Differentiable solutions of the second order elliptic equation

Subject Local and nonlocal boundary value problems for partial differential equations
Title Differentiable solutions of the second order elliptic equation
Author(s) Mukhtarbay Otelbaev, Kordan Ospanov
Keywords elliptic equation, intermediate coefficient, Lorentz space
Abstract We study the second order elliptic equation with discontinuous intermediate coefficients. Suppose that the variable coefficients and the right-hand side of this equation belong to some space M. We find the necessary and sufficient conditions on M for continuous differentiability of the solution to equation, when M is a space of type F or a symmetric space, or one of a Sobolev and Besov space.