Abstract: | A linear terminal problem of optimal control with a piecewise-linear terminal constraints is considered. On the base of the concept of a support the optimality criterion is proved and sufficient optimality condition in the form of the maximum principle is formulated. The support enables us to choose from the set of the Lagrange vectors a special one which in the terminology of linear programming is called the basic vector 1]. In the case of nondegeneracy of the support control the sufficient condition under question is proved to be necessary condition |