LFG semantics via Constraints

To: linear@cs.stanford.edu
Subject: LFG semantics via Constraints
From: Vijay Saraswat <saraswat@parc.xerox.com>
Date: Tue, 27 Apr 1993 10:09:52 PDT
Approved: types@dcs.gla.ac.uk

To make up for my previous contretemps, I offer the following
meaningful post. The paper deals with the use of (tensor, -o)-fragment
of first-order LL instead of the typed lambda-calculus to assemble
meanings of natural language utterances from the meanings of
constituent phrases.

The paper appears in the proceedings of EACL '93 (European Association
for Computational Linguistics, I think). It is available via anonymous
ftp on parcftp.xerox.com as

       pub/ccp/nl/eacl93-lfg-sem.{dvi,ps}.

Vijay
--------------

        	LFG Semantics via Constraints

     Mary Dalrymple    John Lamping    Vijay Saraswat
       {dalrymple, lamping, saraswat}@parc.xerox.com

		Xerox PARC
	   3333 Coyote Hill Road
		Palo Alto
	       CA 94304 USA

ABSTRACT

Semantic theories of natural language associate meanings with
utterances by providing meanings for lexical items and rules for
determining the meaning of larger units given the meanings of
their parts.  Traditionally, meanings are combined via function
composition, which works well when constituent structure trees
are used to guide semantic composition.  More recently, the
*functional structure* of LFG has been used to provide the
syntactic information necessary for constraining derivations of
meaning in a cross-linguistically uniform format.  It has been
difficult, however, to reconcile this approach with the
combination of meanings by function composition.  In contrast to
compositional approaches, we present a deductive approach to
assembling meanings, based on reasoning with constraints, which
meshes well with the unordered nature of information in the
functional structure.  Our use of *linear logic* as a `glue' for
assembling meanings also allows for a coherent treatment of
modification as well as of the LFG requirements of completeness
and coherence.