A posteriori error estimates in finite element methods for general Friedrichs' systems

In this paper we develop and analyse a new a posteriori error estimator for general Friedrichs' systems valid for most classical finite element approximations. This error estimator is based on comparison between an appropriate norm of the exact error, and the L-2-norm of the residuals of the approximate solution. We prove that the estimator is independent of the dimension of the space and of the numerical approximation method used. Moreover the,global majoration and local minoration constants are independent of the shape of the mesh. (C) 2000 Elsevier Science S.A. All rights reserved.