gideon%edai.edinburgh.ac.uk@CS.UCL.AC.UK (Gideon Sahar) (01/29/86)
EDINBURGH AI SEMINARS
Date: 29th January l985
Time: 2.00 p.m.
Place: Department of Artificial Intelligence
Seminar Room - F10
80 South Bridge
EDINBURGH.
Dr. Ewan Klein, Centre for Cognitive Studies, University of Edinburgh
will give a seminar entitled - "Integrating syntax and semantics :
unification categorial grammar as a tool for a natural language
processing".
This talk will report on work carried out at the Centre for Cognitive
Science By Henk Zeevat, Jo Calder and Ewan Klein as part of an ESPRIT
project on natural language and graphics interfaces to a knowledge-base.
In recent years there has been a surge of interest in syntactic
parsers which exploit linguistically-motivated non-transformatinal
grammar formalisms: instances are the GPSG chart parser at
Hewlett-Packard, Palo Alto, and the PATR-II parser at SRI, Menlo Park.
By contrast, progress in the development of tractable, truth-conditional
semantic formalisms for parsing has lagged behind.
Unification categorial grammar (UCG) employs three resources which
significantly improve this situation. The first is Kamp's theory of
Discourse Representation: this is essentially a first-order calculus
which nevertheless provides a more elegant treatment of NL anaphora and
quantification than standard first-order logic.
Second, the grammar encodes both syntactic and semantic information in
the same data structures, namely directed acyclic graphs, and
manipulates them with same operation, namely unification. Third, the
fundamental grammar rule is that of categorial grammar, namely
functional application. Since the grammar objects contain both
syntactic and semantic information, any rule application will
simultaneously produce syntactic and semantic results.
UCG translates readily into a PATR-like declarative formalism, for
which Calder has written a Prolog implementation called PIMPLE.