Development of logic programming, logic grammar methodologies and related theories for solving interesting problems in computational linguistics, deductive databases and intelligent systems. Sample applications using these methodologies include: an English parser using linguistic theory by Chomsky known as Barriers; a translator of American Sign Language into database consultation language, an automatic design system that uses constraint logic programming for producing computer configurations upon demand; a typed hierarchy system for deductive databases; a front end for consulting databases in English, Spanish or French; a generator of machine error messages in English using Chomsky's Government-Binding theory; a French/English translator for agricultural reports; etc.

Editorial Activities: Area Editor, Journal of Logic Programming; Editorial Board Member, International Journal of Expert Systems. Editorial Board Member, Computational Intelligence.