In this note we refine strategies of the so called
dual-weighted-residual (DWR) approach to
a posteriori error control for FE-schemes. We derive rigorous error bounds, especially we control the approximation process of the (unknown) dual solution entering the proposed estimate.
AMS Subject Classifications: 65N30 - 65N15 (primary) - 35J85 (secondary)
Keywords A posteriori error estimate - variational equation - variational inequality - finite element method - adaptivity