| Abstract: | In this paper, we investigate the error estimates and
superconvergence property of mixed finite element methods for
elliptic optimal control problems. The state and co-state are
approximated by the lowest order Raviart-Thomas mixed finite element
spaces and the control variable is approximated by piecewise
constant functions. We derive $L^2$ and $L^\infty$-error
estimates for the control variable. Moreover, using a recovery
operator, we also derive some superconvergence results for the
control variable. Finally, a numerical example is given to
demonstrate the theoretical results. |
