| Abstract: | In this paper, we investigate the error estimates of mixed finite elementmethods for optimal control problems governed by general elliptic equations. Thestate and co-state are approximated by the lowest order Raviart-Thomas mixed finiteelement spaces and the control variable is approximated by piecewise constant functions.We derive $L^2$ and $H^{-1}$-error estimates both for the control variable and the statevariables. Finally, a numerical example is given to demonstrate the theoretical results. |
