Subelliptic nonlinear oblique derivative problems. (English) Zbl 0582.35022

The author extends some known regularity results of a linear oblique derivative problem to a nonlinear problem of the form \[ F(x,u,\nabla u,\nabla^ 2u)=0\quad in\quad \Omega;\quad f(x,u,\nabla u)=0\quad in\quad \partial \Omega \] using Bony’s theory of paradifferential operators.


35G30 Boundary value problems for nonlinear higher-order PDEs
35B65 Smoothness and regularity of solutions to PDEs
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