Reference Resolution

SL is not convenient for representing directly
the meaning of referring expressions because (as
in FOL) the extent of a quantifier in a formula
cannot be extended easily to span variables in
subsequent formulas. We therefore use Discourse
Logic (DL), which is SL extended with
DRSes and ®-expressions as in (Blackburn and
Bos, 2000) (which is based on Discourse Representation
Theory (Kamp and Reyle, 1993) and
its recent extensions for dealing with presuppositions).
6 This approach (like other dynamic semantics
approaches) supports the introduction
of entities that can later be referred back to,
and explains when indefinite NPs should be in-
terpreted as existential or universal quantifiers
(such as in the antecedent of conditionals). The
reference resolution framework from (Blackburn
and Bos, 2000) provides a basis for finding all
possible resolutions, but does not specify which
one to choose. We are working on a probabilistic
reference-resolution module, which will pick
from the legal resolutions the most probable one
based on features such as: distance, gender, syntactic
place and constraints, etc.
5E.g. there is a strong preference for ‘each’ to take
wide scope, a moderate preference for the first quantifier
in a sentence to take wide scope, and a weak preference
for a quantifier of the grammatical subject to take wide
scope.
6Thus, the URs calculated from parse trees are actually
URs of DL formulas. The scope resolution phase
resolves the URs to explicit DL formulas, and the reference
resolution phase converts these formulas to SL
formulas.