A Finite-State approach to the Event Calculus and Type Coercion

Abstract

The Event Calculus (EC) and Finite-State Temporality are two very different formalisms that both address Temporal Semantics. The link between these formalisms is Monadic Second-Order Logic (MSO). Real-line models for the EC are shown, under certain circumstances, to be transformable into finite, discrete string models. These circumstances are those suitable for applying the EC to temporal semantics. The strings are shown to satisfy Monadic Second-Order formulas translated from EC-formulas, indicating the entire real-line is not necessary for tempo ral semantics, EC-predicates can be replaced with MSO-formulas, and discrete models used. Strings forming regular languages are showm to have their limits in the de scription of natural language semantics. Introducing context-free languages im pacts on certain relations used in FST, leading to an increase in complexity.