Electronic Journal of Differential Equations,
Vol. 2000(2000), No. 05, pp. 1-10.

Title: Nonlinear perturbations of systems of partial
       differential equations with constant coefficients

Author: C. J. Vanegas (Universidad Simon Bolivar, Venezuela)

Abstract: 
 In this article, we show the existence of solutions to
 boundary-value problems, consisting of nonlinear systems of
 partial differential equations with constant coefficients. For
 this purpose, we use the right inverse of an associated operator
 and a fix point argument. As illustrations, we apply this method
 to Helmholtz equations and to second order systems of elliptic
 equations.

Submitted April 6, 1999. Published January 8, 2000.
Math Subject Classifications: 35F30, 35G30, 35E20.
Key Words: Right inverse; nonlinear differential equations; 
           fixed point theorem.