Name
Abstract | ||
|---|---|---|
We present the results of an investigation into how the set of elementary trees of a Lexicalized Tree Adjoining Grammar can be represented in the lexical knowledge representation language DATR (Evans & Gazdar 1989a,b). The LTAG under consideration is based on the one described in Abeille et al. (1990). Our approach is similar to that of Vijay-Shanker & Schabes (1992) in that we formulate an inheritance hierarchy that efficiently encodes the elementary trees. However, rather than creating a new representation formalism for this task, we employ techniques of established utility in other lexically-oriented frameworks. In particular, we show how DATR's default mechanism can be used to eliminate the need for a non-immediate dominance relation in the descriptions of the surface LTAG entries. This allows us to embed the tree structures in the feature theory in a manner reminiscent of HPSG subcategorisation frames, and hence express lexical rules as relations over feature structures. Vijay-Shanker & Schabes (1992) have drawn attention to the considerable redundancy inherent in LTAG lexicons that are expressed in a flat manner with no sharing of structure or properties across the elementary trees1. In addition to theoretical considerations, one practical consequence of such redundancy is that maintenance of the lexicon becomes very difficult. One way to minimise redundancy is to adopt a hierarchical lexicon structure with inheritance and lexical rules. Vijay- Shanker & Schabes outline such a view of an LTAG lexicon which is loosely based on that of Flickinger (1987) but tailored for LTAG trees rather than HPSG subcategorization lists. |
Year | Venue | Keywords |
|---|---|---|
1995 | Clinical Orthopaedics and Related Research | tree structure,knowledge representation |
Field | DocType | Volume |
Inheritance hierarchy,Tree-adjoining grammar,Head-driven phrase structure grammar,Dominance relation,Computer science,DATR,Tree structure,Artificial intelligence,Natural language processing,Formalism (philosophy),Representation language,Machine learning | Journal | cmp-lg/950 |
ISSN | Citations | PageRank |
Proceedings of TAG+3, 1994 | 2 | 0.40 |
References | Authors | |
11 | 3 | |
Name | Order | Citations | PageRank |
|---|---|---|---|
| Roger Evans | 1 | 344 | 55.12 |
| Gerald Gazdar | 2 | 139 | 26.96 |
| David J. Weir | 3 | 840 | 83.84 |