Abstracts of HCRC Research papers, 1999

Renate Henschel & John Bateman
Application-driven automatic subgrammar extraction

The space and run-time requirements of broad coverage grammars appear for many applications unreasonably large in relation to the relative simplicity of the task at hand. On the other hand, handcrafted development of application-dependent grammars is in danger of duplicating work which is then difficult to re-use in other contexts of application. To overcome this problem, we present in this paper a procedure for the automatic extraction of application-tuned consistent subgrammars from proved large-scale generation grammars. The proceedure has been implemented for large-scale systemic grammars and builds on the formal equivalence between systemic grammars and typed unification based grammars. Its evaluation for the generation of encyclopedia entries is described and directions of future development, applicability, and extensions are discussed.
(March 1999: 8 pages)
Ref. No. HCRC/RP-101 Price: UKL ???

Massimo Poesio
Utterance Processing and Semantic Underspecification

We propose a theory of utterance processing meant to clarify the respective roles of incrementality and underspecification in semantic interpretation. After reviewing the available psychological evidence, we provide (i) a formal model of the semantic interpretations constructed by the language processor while processing utterances in an incremental fashion, including the cases in which these interpretations are semantically underspecified; and (ii) a formal model of the disambiguation process, which we use to account for the psychological findings concerning two areas of semantic interpretation: lexical disambiguation and pronoun resolution, emphasizing similarities and differences between the two processes. We also make a few preliminary hypotheses about scope disambiguation. Some of the novel aspects of our proposal include the emphasis on psychological evidence, using a standard logical formalism to characterize semantically underspecified interpretations rather than logics specially developed for this purpose, and the role in the theory of logics for defeasible reasoning, which are used not only to account for the evidence about disambiguation, but more in general to provide a formal characterization of ambiguity.
(April 1999: 122 pages)
Ref. No. HCRC/RP-103 Price: UKL ???