Encoding Lexicalized Tree Adjoining Grammars with a
Nonmonotonic Inheritance Heirarchy

Roger Evans, Gerald Gazdar, and David Weir
ITRI-95-7
May 1995

This paper shows how DATR, a widely used formal language for lexical
knowledge representation, can be used to define an LTAG lexicon as an
inheritance hierarchy with internal lexical rules. A bottom-up featural
encoding is used for LTAG trees and this allows lexical riles to be 
implemented as co-variation constraints within feature structures. 
Such an approach eliminates the considerable redundancy otherwise 
associated with an LTAG lexicon.