Set Differential Equations and Flow Invariance

The study of Set Differential Equations is initiated in the metric space of nonempty, compact, convex subsets of , endowed with the Hausdorff metric. The existence of a generalized solution for the associated initial value problems is proved when the function involved does not satisfy any continuity assumptions. Utilizing the ideas of nonsmooth analysis, a proximal aiming condition is employed to investigate the weak and strong invariance for these solutions.