Comparison theorems for nonlinear elliptic systems of second order with applications (Q1071173)

The authors consider general nonlinear elliptic systems with elliptic operators of the form \[ f^ k(u)\equiv f^ k(x,u,u^ k_ x,u^ k_{xx}),\quad k=1,2,...,n \] where u and x are vectors in \(R^ n\). They then prove comparison results similar to the classical ones for elliptic problems. They give some interesting applications to the problems of vibrating plates and membranes.