Simpler TAG semantics through synchronization

Abstract

In recent years Laura Kallmeyer, Maribel Romero, and their collaborators have led research on TAG semantics through a series of papers refining a system of TAG semantics computation. Kallmeyer and Romero bring together the lessons of these attempts with a set of desirable properties that such a system should have. First, computation of the semantics of a sentence should rely only on the relationships expressed in the TAG derivation tree. Second, the generated semantics should compactly represent all valid interpretations of the input sentence, in particular with respect to quantifier scope. Third, the formalism should not, if possible, increase the expressivity of the TAG formalism. We revive the proposal of using synchronous TAG (STAG) to simultaneously generate syntactic and semantic representations for an input sentence. Although STAG meets the three requirements above, no serious attempt had previously been made to determine whether it can model the semantic constructions that have proved difficult for other approaches. In this paper we begin exploration of this question by proposing STAG analyses of many of the hard cases that have spurred the research in this area. We reframe the TAG semantics problem in the context of the STAG formalism and in the process present a simple, intuitive base for further exploration of TAG semantics. We provide analyses that demonstrate how STAG can handle quantifier scope, long-distance WH-movement, interaction of raising verbs and adverbs, attitude verbs and quantifiers, relative clauses, and quantifiers within prepositional phrases.