On expressing lexical generalizations in HPSG

This paper investigates the status of the lexicon and the possibilities for expressing lexical generalizations in the paradigm of Head-Driven Phrase Structure Grammar (HPSG). We illustrate that the architecture readily supports the use of implicational principles to express generalizations over a class of word objects. A second kind of lexical generalizations expressing relations between classes of words is often expressed in terms of lexical rules. We show how lexical rules can be integrated into the formal setup for HPSG developed by King (1989, 1994), investigate a lexical rule specification language allowing the linguist to only specify those properties which are supposed to differ between the related classes, and define how this lexical rule specification language is interpreted. We thereby provide a formalization of lexical rules as used in HPSG.