  It is well-known that the Lyapunov exponent plays a fundamental role in
dynamical systems. In this note, we propose an alternative definition of
Lyapunov exponent in terms of Lipschitz maps, which are not necessarily
differentiable. We show that the results which are valid to standard discrete
dynamical systems are also valid in this new context. Therefore, this novel
approach expands the range of applications of the dynamical systems theory.
