Unified Representation of Typological, Absolute and Relational Predicates

In this paper, we show how to use a functional representation to implement different kinds of referential predicates (relational, absolute and typological, according to the typology proposed by Dale and Reiter). This implementation is intended to resolve extensional referring expressions in a practical dialogue system. We first show that all kinds of referential predicates are context-dependent and are essentially relative, whether they rely on type of entities, intrinsic properties or relational properties. We then argue that a functional approach is necessary to overcome the lack of expressiveness of predicative approaches. Indeed, phenomena like vague predicates or relational properties are very expensive to handle within a predicative approach, since this latter does not account for the matter of degree and dynamicity introduced by these phenomena in a dialogue context. Designers of dialogue systems are thus often led to use specific heuristics for resolving relational referring expressions, and adopt a simplified view on typological and absolute predicates. As we are interested in providing a unified framework for extensional reference resolution in a human computer dialogue system, we detail how to use our functional representation model for referential predicates into a generic resolution algorithm.