Cost-Optimal Planning With Landmarks

Abstract

Planning landmarks are facts that must be true at some point in every solution plan. Previous work has very successfully exploited planning landmarks in satisficing (non-optimal) planning. We propose a methodology for deriving admissible heuristic estimates for cost-optimal planning from a set of planning landmarks. The resulting heuristics fall into a novel class of multi-path dependent heuristics, and we present a simple best-first search procedure exploiting such heuristics. Our empirical evaluation shows that this framework favorably competes with the state-of-the-art of cost-optimal heuristic search.