On optimal parameter selection

Pontryagin's results on optimal parameter selection problems 1, p. 193] have been found to contain some errors, as reported in Boltyanskii 2, p. 263] and Hofer and Sagirow 4]. In this note, it is shown that Boltyanskii's results (on optimal parameters) are easily derived from Gamkrelidze's general maximum principle 3], which, in contrast to the former, also yields an explicit solution to the problem in certain special cases.