Conley barriers and their applications: Chain-recurrence and Lyapunov functions

Given a compact metric space X and a continuous map f from X to itself, we construct a barrier function for chain-recurrence. We use it to endow the space of chain-transitive components with a non-trivial ultrametric distance and to construct Lyapunov functions for f. Most of these constructions are then generalized on an arbitrary separable metric space to a continuous compactum-valued map. (C) 2009 Elsevier B.V. All rights reserved.