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 ???