Paper: Applying Lexical Rules Under Subsumption

ACL ID C96-1092
Title Applying Lexical Rules Under Subsumption
Venue International Conference on Computational Linguistics
Session Main Conference
Year 1996

Lexical rules are used in constraint- based grammar formalisms such as llead-Driven l)hrase Structure Grammar (IIPSG) (Pollard and Sag 1994) to ex- press generalizations atnong lexical en- tries. '['his paper discusses a number of lexical rules from recent I[PSG analy- ses of German (tlinri<;hs and Nakazawa 1994) and shows that the grammar in some cases vastly overgenerates and in other cases introduces massive spurious structural ambiguity, if lexical rules ap: ply under unification. Such l)rot)lems of overgeneration or spurious ambiguity do not arise, if a lexical rule al)plies to a given lexical ent;ry iff the lexical entry is subsumed by the left:hand side of the lexical rule. I,'inally, the paper discusses computational consequcnce~s of at)plying lexical rules under subsuml)tion.