EXISTENCE THEOREMS OF OPTIMAL CONTROL PROBLEMS IN BANACH SPACES*

THE SUBJECT of optimization problems in the theory of distributed parameter control systems has gained much interest. This is readily seen in the survey on the subject by Robinson [20] and Russell [21]. Linear systems governed by partial differential equations have been given the most attention, cf. Axelband [2], Aziz et al. [3], Balakrishnan [4] and Lions [18], to nam