Pontryagin’s maximum principle in its infinite dimensional version provides (separate) necessary and sufficient conditions for both time and norm optimality for the system y′ = Ay + u (A the infinitesimal generator of a strongly continuous semigroup). Among controls that satisfy the maximum principle, a smoothness distinction can be defined in terms of smoothness of the final value of the costate. This paper addresses some issues related to this distinction.
@article{1527, title = {Regular and Strongly Regular Time and Norm Optimal Controls}, journal = {CUBO, A Mathematical Journal}, volume = {10}, year = {2008}, language = {en}, url = {http://dml.mathdoc.fr/item/1527} }
Fattorini, H. O. Regular and Strongly Regular Time and Norm Optimal Controls. CUBO, A Mathematical Journal, Tome 10 (2008) . http://gdmltest.u-ga.fr/item/1527/