ERROR ESTIMATORS USING CONSTITUTIVE LAWS

In this Note, we present an a posteriori error estimator for the diffu sion problem, which evaluates the error on the constitutive law: paral lel to del (u) over tilde(h)-(p) under bar(h)parallel to 0,Omega, wher e (u) over tilde(h) is a conforming ''approximation'' of the primal va riable u and (p) under bar(h) is an admissible approximation of the de l u obtained by post-processing from the P-1 nonconforming approximati on of u. The method is extended to Stokes problem. Similar results can be obtained for the equation of linear elasticity. (C) Academie des S ciences/Elsevier, Paris.