Describing discourse semantics

Descriptions. In recent years, both formal and computational linguistics have been exploiting descriptions of structures where previously the structures themselves were used. The practice started with (Marcus et al., 1983), who demonstrated the value of (syntactic) tree descriptions for near-deterministic incremental parsing. Vijay-Shankar (Vijay-Shankar and Joshi, 1988; Vijay-Shankar, 1992) used descriptions to maintain the monotonicity of syntactic derivations in the framework of Feature-Based Tree Adjoining Grammar. In semantics, both (Muskens, 1997) and (Egg et al., 1997) have shown the value of descriptions as an underspecified representation of scope ambiguities. The current paper further extends the use of descriptions, from individual sentences to discourse, showing their benefit for incremental, near-deterministic discourse processing. In particular, we show that using descriptions to describe the semantic representation of discourse permits: (1) a monotone treatment of local ambiguity; (2) a deterministic treatment of global ambiguity; and (3) a distinction to be made between “simple” local ambiguity and “garden-path” local ambiguity.