This paper develops nonsmooth Lyapunov stability theory and LaSalle's
invariance principle for a class of nonsmooth Lipschitz continuous Lya
punov functions and absolutely continuous state trajectories. Computab
le tests based on Filipov's differential inclusion and Clarke's genera
lized gradient are derived. The primary use of these results is in ana
lyzing the stability of equilibria of differential equations with disc
ontinuous right-hand side such as in nonsmooth dynamic systems or vari
able structure control.