Paper: User-Defined Nonmonotonicity In Unification-Based Formalisms

ACL ID P95-1009
Title User-Defined Nonmonotonicity In Unification-Based Formalisms
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 1995

A common feature of recent unification- based grammar formalisms is that they give the user the ability to define his own structures. However, this possibility is mostly limited and does not include non- monotonic operations. In this paper we show how nonmonotonic operations can also be user-defined by applying default lo- gic (Reiter, 1980) and generalizing previous results on nonmonotonic sorts (Young and Rounds, 1993). 1 Background Most of the more recent unification-based forma- lisms, such as TFS (Emele and Zajac, 1990), UD (Johnson and Rosner, 1989), CUF (DSrre and Eisele, 1991), and FLUF (StrSmb~ick, 1994), provide some possibility for the user to define constructions of his own. This possibility can be more or less power- ful in different formalisms. There are, however, se- veral c...