Inclusions aux dérivées partielles gouvernant des contrôles de rétroaction

One derives partial differential inclusions of hyperbolic type the solutions of which are feedbacks governing the viable (controlled invariant) solutions of a control system. One also shows that the tracking property leads to such partial differential inclusions. After deriving some properties from the viability theorems, one states a variational principle and an existence theorem of a (single-valued contingent) solution to such an inclusion.