Variation method of solving the irregular oblique derivative problem for elliptic equations of second order

Abstract

This paper deals with irregular oblique derivative boundary value problems for nonlinear elliptic equations of second order. The uniformly elliptic equations of second order are reduced to elliptic complex systems of first order, and then the irregular oblique derivative problem for the equations of second order is transformed into the Riemman-Hilbert problem for the complex system of first order. The approximate solutions of the boundary value problem are obtained by the variation