TY - JOUR T1 - Error Estimates and Superconvergence of RT0 Mixed Methods for a Class of Semilinear Elliptic Optimal Control Problems JO - Numerical Mathematics: Theory, Methods and Applications VL - 4 SP - 637 EP - 656 PY - 2013 DA - 2013/06 SN - 6 DO - http://doi.org/10.4208/nmtma.2013.1230nm UR - https://global-sci.org/intro/article_detail/nmtma/5923.html KW - Semilinear elliptic equations, optimal control problems, superconvergence, error estimates, mixed finite element methods. AB -

In this paper, we will investigate the error estimates and the superconvergence property of mixed finite element methods for a semilinear elliptic control problem with an integral constraint on control. The state and co-state are approximated by the lowest order Raviart-Thomas mixed finite element and the control variable is approximated by piecewise constant functions. We derive some superconvergence properties for the control variable and the state variables. Moreover, we derive $L^∞$- and $H^{-1}$-error estimates both for the control variable and the state variables. Finally, a numerical example is given to demonstrate the theoretical results.