Fast probabilistic plan recognition without plan library

Instead of using a plan library, the recognizer introduced in this paper uses a compact structure called PGoalGraph to represent goals, actions and states of the world. This method doesn´t suffer the problem of acquisition and hand-coding a larger plan library as traditional methods do. The recognizer also extends classical methods in two directions. First, it doesn´t make the assumption that all the effects of an action are deterministic. Second, the recognizer can produce an optimal plan instead of producing a set of equally plausible plan hypothesis. Since the recognizer is a domain independent one, the method can be adapted in almost every domain.