Approximate controllability and homogenization of a semilinear elliptic problem ✩

The L2- and H1-approximate controllability and homogenization of a semilinear elliptic boundary-value problem is studied in this paper. The principal term of the state equation has rapidly oscillating coefficients and the control region is locally distributed. The observation region is a subset of codimension 1 in the case of L2-approximate controllability or is locally distributed in the case of H1-approximate controllability. By using the classical Fenchel–Rockafellar’s duality theory, the existence of an approximate control of minimal norm is established by means of a fixed point argument. We consider its asymptotic behavior as the rapidly oscillating coefficients H-converge. We prove its convergence to an approximate control of minimal norm for the homogenized problem.  2003 Elsevier Inc. All rights reserved.