Danilin, A. R. Approximation of a singularly perturbed elliptic optimal control problem with geometric constraints on the control. (English) Zbl 1122.49304 Danilin, A. R. (ed.), Asymptotic expansions, approximation theory, topology. Transl. from the Russian. Moscow: Maik Nauka / Interperiodica. Proceedings of the Steklov Institute of Mathematics 2003, Suppl. 1, S45-S53 (2003). MSC: 49K40 35J25 49J20 93C70 49M30