Summary. This note studies the strong invariance propertyo fadiscontinuous differential inclusion in whicht he righth and side is the sum of an almost upper semicontinuous dissipativea nd an almost lowers emicontinuous one-sided Lipschitz multifunction. Ac haracterization is obtained in terms of aHamilton-Jacobi inequality.
1I ntroduction and AssumptionsWe extend ac haracteriz ation of strong invariance that wasrecently provedin [16] to an onautonomous s y stem with weaker data assumptions. Consider the control s y stem modelled as ad ifferential inclusionwhere the given multifunction F : I×IR n → 2 IR n has compact convex values and I⊆IR is an open interval with [ t 0 ,t 1 ) ⊆I. The focus in this paper is on the case where the multifunction F has the formwhere D is upper semicontinuous and dissipative in x and G is lower semicontinuous and one-sided Lipschitz ; precise assumptions will be given below. We briefly recall the main concepts of invariant s y stems theory for the s y stem (1) using the language and notation from [6,7]. In addition to F , a closed set S ⊆ IR n is also given. The pair ( S, F ) is weakly invariant (respectively , strongly invariant) if for every [ t 0 , t 1 ) ∈Iand every x 0 ∈ S , at least one (respectively , every ) solution x ( · ) of (1) satisfies x ( t ) ∈ S for all t ∈ [ t 0 ,t 1 ). We refer the reader to [5,13,15] for the history of invariance theory , which is elsewhere called viability theory [1,2].