Hierarchical a posteriori error estimator. Application to mixed finite elements (Q1266312)

The authors propose a generalization of the hierarchical a posteriori error estimator of \textit{R. E. Bank} and \textit{A. Weiser} [Math. Comput. 44, 283-301 (1985; Zbl 0569.65079)] to mixed formulations. They consider the cases of conforming and nonconforming approximations, with or without numerical integration. Unfortunately, the examples of application refer only to mixed dual formulation of the Dirichlet problem for the Laplace operator.