A sharp angle inequality for a pair of elliptic operators in the case of a domain with conical point (Q2735862)

The investigation of the solvability of the nonlinear Dirichlet problem by applying topological methods is based on coercive estimates. The sharp angle inequality for a pair of elliptic operators is an example of such an estimate. For the first time this inequality was obtained by O. A. Ladyzhenskaya for a pair of second order linear elliptic operators in a domain with an infinitely smooth boundary. For higher-order operators such an inequality was proved by \textit{I. V. Skrypnik} [Nonlinear elliptic boundary value problems, Leipzig: Teubner (1986; Zbl 0617.35001)]. In this article the sharp angle inequality for a pair of high order elliptic operators in a domain with conical point in terms of weighted norms has been proven.