Processing Complex Noun Phrases In A Natural Language Interface To A Statiscal Database

Analysis of a corpus of queries to a statistical database has shown considerable variation in the location and order of modifiers in complex noun phrases. Nevertheless, restrictions can be defined on nominal modification because of certain correspondences between nominal modifiers and the role they fulfill in a statistical database, notably that the names of database tables and columns, and values of columns, are all determined by the modifiers. These restrictions are described. Incorporating these restrictions into Head-Driven Phrase Structure Grammar (HPSG) has caused us to examine the treatment of nominal modification in HPSG. A new treatment is proposed and an implementation within an HPSG based natural language front-end to a statistical database is described.