On the regularity of optimal controls

We outline some recent results on the regularity of optimal controls. We formulate the general regularity problem for open-loop and closed-loop controls, and explain how results for the open-loop case have implications for the closed-loop case as well. We then describe a number of results on the regularity of open-loop controls.Partially supported by a fellowship from the Alfred P. Sloan Foundation.Partially supported by NSF Grant No. DMS83-01678-01.