Full paper in PDF:
$%A. Osses and J.-P. Puel, On the controllability of the Laplace equation observed on an interior curve, Rev. Mat. Complut. 11 (1998), no. 2, 403441.%$

On the Controllability of the Laplace Equation Observed on an Interior Curve
Axel OSSES and Jean-Pierre PUEL
Centre de Mathématiques Appliquées
Ecole Polytechnique
91128 Palaiseau Cedex
Paris France
Université de Versailles Saint-Quentin
and Centre de Mathématiques Appliquées
Ecole Polytechnique
91128 Palaiseau Cedex
Paris France

Received: February 11, 1997
Revised: April 15, 1997
ABSTRACT

The boundary approximate controllability of the Laplace equation observed on an interior curve is studied in this paper. First we consider the Laplace equation with a bounded potential. The  p
L  (1< p < oo  ) approximate controllability is established and controls of   p
L  -minimal norm are built by duality. At this point, a general result which clarifies the relationship between this duality approach and the classical optimal control theory is given. The results are extended to the Lp  (1> p<  oo  ) approximate controllability with quasi bang-bang controls and finally to the semilinear case with a globally Lipschitz non linearity by a fixed point method. A counterexample shows that the globally Lipschitz hypothesis is essential. To compute the control, a numerical method based in the duality technique is proposed. It is tested in several cases obtaining a fast behavior in the case of fixed geometry.

1991 Mathematics Subject Classification: 35B37, 93B40, 93B06, 93C10.