An abstract theory for mixed approximations of second order elliptic problems. (English) Zbl 0711.65091

The authors present an abstract theory for discretization of second order elliptic problems using mixed finite elements based on minimal hypotheses. A theorem on convergence and error estimates is presented. Some new properties of the new elements are explained.
Reviewer: P.K.Mahanti


65N30 Finite element, Rayleigh-Ritz and Galerkin methods for boundary value problems involving PDEs
65N15 Error bounds for boundary value problems involving PDEs
35J25 Boundary value problems for second-order elliptic equations