Pereira, F. C. (1987). Grammars and logics of partial information. In Proc. 4th ICLP (pp. 989-1013).
Abstract
This paper is an informal survey of models of grammatical categories in unification-based formalisms from computational linguistics and their relationship to current logic programming concepts. The basic notion of partiality in the informational content of grammatical categories is introduced, and specific automata-theoretic, denotational and logical models of partial information are outlined. The expression of disjunction, negation, inheritance and indeterminate constraints in categories is also discussed.