The Association for Mathematics of Language and The Institute for Research in Cognitive Science (IRCS) University of Pennsylvania
Abstract
This paper presents a precise characterization of the underspecification found in Lexicalized Tree Adjoining Grammars, and shows that, in a sense, the same degree of underspecification is found in Lexicalized D-Tree Substitution Grammars. Rather than describing directly the nature of the elementary objects of the grammar, we achieve our objective by formalizing the way in which underspecification in the derived objects is interpreted: i.e., how trees are read off from derived tree descriptions. Valid tree descriptions for ltag turn out to be those that have a single acceptable interpretation, whereas those for ldsg may have multiple interpretations. In other respects, there is no difference in the way in which ltag and ldsg tree descriptions are interpreted
