Paper: Using Constraints In A Constructive Version Of GPSG

ACL ID C88-2151
Title Using Constraints In A Constructive Version Of GPSG
Venue International Conference on Computational Linguistics
Session Main Conference
Year 1988

Complex categories are caracteristic of unification grammars as for example GPSG [Shieber86a]. They are sets of pairs of feature.s and values. The unification, which can be applied to two or more categories, is the essential operation. The papers of [Shieber85], [Barton85] and [Ristad86] deal with the influence of complex categories on the efficiency of the parsing algorithm. This is one problem from using complex categories, another one arises when using a constructive version of GPSG (see [Busemann/Hanensehild88] in this volume). Namely that the appli- cation of admissibility conditions, e.g. LP statements and FCRs 1, to a local tree t is prevented because particular feature values of eat- egories in t are not yet specified, but they will be instantiated later somewhere else in the compl...