THE NONLINEAR OBLIQUE DERIVATIVE PROBLEM IN THE PLANE

The aim of this Note is to prove an existence and uniqueness result co ncerning the oblique derivative problem for nonlinear elliptic discont inuous operators in the plane. As a particular case, we obtain an exis tence and uniqueness result for linear equations with measurable and b ounded coefficients. In this way we extend the classical result of Ber nstein (see [1]), related to the Dirichlet problem, to the oblique der ivative problem.