A POSTERIORI ERROR-ESTIMATES BASED ON HIERARCHICAL BASES

The authors present an analysis of an a posteriori error estimator bas ed on the use of hierarchical basis functions. The authors analyze non linear, nonselfadjoint, and indefinite problems as well as the selfadj oint, positive-definite case. Because both the analysis and the estima tor itself are quite simple, it is easy to see how various approximati ons affect the quality of the estimator. As examples, the authors appl y the theory to some scalar elliptic equations and the Stokes system o f equations.