Building and Maintaining a Semantically Adequate Lexicon Using Cyc

Abstract

The Cyc lexicon is a broad-coverage lexicon which is being constructed as a component of the Cyc KB a very large repository of common sense knowledge. Building and maintaining a large lexicon in conjunction with a knowledge base and inference engine is a much different task than building a stand-alone lexicon, or a lexicon which relies on a small internal or external ontology. In building the Cyc lexicon, we have been concerned not with demonstrating or testing theoretical claims, but with creating a practical tool, since Cyc-based applications demand a certain level of functionality from the lexicon. As such, our work is theory-driven only to the extent that a particular theory proves useful to us. In this chapter we discuss a number of issues which have arisen in developing the Cyc lexicon, including the feasibility of taking advantage of semantic classification schemes as a shortcut to hand-entering lexical information; distinguishing between world and lexical knowledge; and providing a level of semantic detail in the lexicon which is compatible with the expressiveness of Cyc’s internal representation language.