Meyer, ChristianRoesch, Arnd2021-12-172021-12-172004-09-012197-8085https://depositonce.tu-berlin.de/handle/11303/15532http://dx.doi.org/10.14279/depositonce-14305An optimal control problem for a 2-d elliptic equation is investigated with pointwise control constraints. This paper is concerned with the discretization of the control by piecewise linear functions. The state and the adjoint state are discretized by linear finite elements. Approximation of order $h$ in the $L^\infty$-norm is proved in the main result. The theoretical result is confirmed by a numerical test.en510 Mathematiklinear-quadratic optimal control problemserror estimateselliptic equationsnumerical approximationcontrol constraintsResearch Paper