The Ramification Problem in the Event Calculus

Abstract

Finding a solution to the frame problem that is robust in the presence of actions with indirect effects has proven to be a difficult task. Examples that feature the instantaneous propagation of interacting indirect effects are particularly taxing. This article shows that an already widely known predicate calculus formalism, namely the event calculus, can handle such examples with only minor enhancements. Introduction The ramification problem, that is to say the frame problem in the context of actions with indirect effects, has attracted considerable attention recently [McCain & Turner, 1995], [Lin, 1995], [Gustafsson & Doherty, 1996], [Sandewall, 1996], [Shanahan, 1997], [Thielscher, 1997], [Kakas & Miller, 1997], [Denecker, et al., 1998]. The purpose of this paper is to demonstrate that the standard benchmark scenarios for the ramification problem can be handled by the event calculus, as presented in Chapter 16 of [Shanahan, 1997], without introducing any significant new logical mac...