Introduction

The work reported here is part of research on the ACQUILEX project which is aimed at the eventual development of a theoretically motivated, but comprehensive and computationally tractable, multilingual lexical knowledge base (LKB) usable for natural language processing, lexicography and other applications. One of the goals of the ACQUILEX project was to demonstrate the feasibility of building an LKB by acquiring a substantial portion of the information semi-automatically from machine readable dictionaries (MRDs). We have paid particular attention to lexical semantic information. Our work therefore attempts to integrate several strands of research:

1. • Linguistic theories of the lexicon and lexical semantics. In this chapter we will concentrate on the lexical semantics of nominals where our treatment is broadly based on that of Pustejovsky (1991), and in particular on his concepts of the generative lexicon and of qualia structure.

2. • Knowledge representation techniques. The formal lexical representation language (LRL) used in the ACQUILEX LKB system is based on typed features structures similar to those of Carpenter (1990, 1992), augmented with default inheritance and lexical rules. Our lexicons can thus be highly structured, hierarchical and generative.

3. • Lexicography and computational lexicography. The work reported here makes extensive use of the Longman Dictionary of Contemporary English (LDOCE; Procter, 1978). MRDs do not just provide data about individual lexical items; our theories of the lexicon have been developed and refined by considering the implicit organization of dictionaries and the insights of lexicographers.

In this chapter we will show how these strands can be combined in developing an appropriate representation for group nouns in the LRL, and in extracting the requisite information automatically from MRDs.