Using default inheritance to describe LTAG

Roger Evans; Gerald Gazdar; David Weir

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Using default inheritance to describe LTAG

Roger Evans·Gerald Gazdar·David Weir

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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.

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Roger Evans, Gerald Gazdar, David Weir. 1995-01-09. Using default inheritance to describe LTAG. https://arxiv.org/abs/cmp-lg/9501001

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