Linguistic Coherence: a Plan-Based Alternative

To fully unders tand a sequence of u t terances , one must be able to infer implici t re la t ionships be tween the ut terances . Al though the ident i f ica t ion of sets of u t terance relat ionships forms the basis for many theories of discourse, the formal iza t ion and recognition of such relat ionships has proven to be an ext remely difficult computa t iona l task. This paper presents a plan-based approach to the representa t ion and recognit ion of implici t re la t ionships be tween ut terances. Relat ionships are formulated as discourse plans, which allows their representation in terms of planning opera tors and their computation via a plan recogni t ion process. By incorpora t ing complex inferent ia l processes relat ing u t te rances into a plan-based f ramework , a formal iza t ion and computability not available in the ear l ie r works is provided.