The Event Calculus as a Linear Logic Program
Vladimir Alexiev · 1995
. The traditional presentation of Kowalski's Event Calculus as a logic program uses Negationas -Failure (NAF) in an essential way to support persistence of fluents. In this paper we present an implementation of Event Calculus as a purely logical (without NAF) Linear Logic (LL) program. This work demonstrates some of the internal non-monotonic features of LL and its suitability for knowledge update (as opposed to knowledge revision). Although NAF is an ontologically sufficient solution to the frame problem, the LL solution is implementationally superior. Handling of incomplete temporal descriptions and support for ramifications (derived fluents) are also considered. Keywords: event calculus, linear logic, negation as failure, knowledge update. 1 Introduction The Event Calculus (EC) of [ Kowalski and Sergot, 1986 ] is a theory of events (actions) and the fluents (predicates) that they precipitate. An important property of the theory is that it is rendered as a logic program, and is thu...