Discontinuous differential equations. I
(Joint review with Zbl 0681.34009). The classical notions of solution, to an ordinary differential equation, are sometimes insufficient. Three generalisations have been proposed (Filippov, Krasovskij, and, implicitly, Hermes). The first part of the paper studies these concepts; it is shown that, in very general circumstances, the last two are equivalent (and sometimes one of the alternative descriptions has a decided advantage over the other). The concepts and results of the first part of this paper are applied in the second part [ibid. 32, 171--185 (1979; Zbl 0681.34009)] to linear differential games with hyperplane targets and feedback-type strategies; and to an example of Nash equilibrium in a non-linear game (the Leitman-Lin model of collective bargaining). Some uniqueness results are obtained, particularly in the context of Hermes's notion of stability with respect to measurement; and applied to time-optimal feedback in linear control. The principal result (Theorem 9.4) is that, for controllable linear single-input systens, the corresponding feedback equation is stable with respect to measurement (while the assertion fails for multi-input systems).
scientific article; zbMATH DE number 3569074