Fixed and Flexible Phrase Structure: Coordination in Tree Adjoining Grammars

Abstract

In this paper, we present an initial formulation of how a combinatory categorial grammar (CCG)-like account of coordination can be constructed in the framework of lexicalized tree adjoining grammar (TAG). In particular, we show how a fixed constituency can be maintained at the level of the elementary trees of lexicalized TAG and yet be able to achieve the kind of flexibility needed for dealing with the so-called non-constituents. In a CCG, being a constituent is the same as being a function. We show that this need not be the case and standard notions of constituency can be maintained. The main idea is that we use the lexicalized trees of TAG as 'structured' categories with the associated functional types. We have not described the coordination schema in detail, we have illustrated our ideas by suitable examples