A fixed-point approximation method for some noncoercive variational problems
This paper deals with the finite-element approximation of some variational problems, namely linear elliptic boundary value problems, variational inequalities, and quasi-variational inequalities with noncoercive operators. To prove optimal L-infinity-error estimates, we introduce a simple and direct argument combining continuous piecewise linear finite elements with the Banach fixed-point theorem. (C) 2000 Elsevier Science Ltd. All rights reserved.
boundary value problem variational inequality quasi-variational inequality finite element fixed point