Optimal control for the conformal Laplacian obstacle problem

We study an optimal control problem associated to the conformal Laplacian obstacle problem on closed n-dimensional Riemannian manifolds with n >2. When the Yamabe invariant of the Riemannian manifold is positive, we show that the optimal controls are equal to their associated optimal states and show the existence of a smooth optimal control which induces a conformal metric with constant scalar curvature. For the standard sphere, we prove that the standard bubbles – namely conformal factor of metrics conformal to the standard one with constant positive scalar curvature – are the only optimal controls and hence equal to their associated optimal state.