A Theory of Granularity and its Application to Problems of Polysemy and Underspecification of Meaning

Communication using natural language is remarkably e cient, by allowing reuse (through the use of generative devices) of a nite vocabulary to describe a potentially innite set of situations. This vocabulary reuse contributes to words having many related senses (polysemy). Further, meanings can be relatively vague or precise; in other words, varying in their degree of speci cation of meaning. I suggest that these problems can be addressed by developing a knowledge representation which makes explicit the notion of granularity. As the grain size changes, we may fold certain distinctions, or split meanings more nely. In this paper, I formalize a theory of granularity and demonstrate how it can be applied to problems of meaning representation. Such a theory requires a world model which provides a rich sortal di erentiation of entities based on the distinctions made by natural language, including the representation of meronymic structure and rei cation. Granularity will be represented in terms of structural operations de ned as abstractions. I illustrate how this applies to problems of polysemy and vagueness in nominalizations, where splitting and folding of meanings are particularly evident.