</term>
for a special type of
<term>
deterministic
#16889These graphs are, in fact,transition graphs for a special type of deterministic finite automaton.
other,0-1-P86-1038,ak
of the two
<term>
formalisms
</term>
.
<term>
Unification-based grammar formalisms
</term>
use
<term>
structures
</term>
containing
#16806We then turn to a discussion comparing the linguistic expressiveness of the two formalisms.Unification-based grammar formalisms use structures containing sets of features to describe linguistic objects.
tech,0-8-P86-1038,ak
to simplify
<term>
formulas
</term>
.
<term>
Unification
</term>
is attractive , because of its generality
#16972This logical model yields a calculus of equivalences, which can be used to simplify formulas.Unification is attractive, because of its generality, but it is often computationally inefficient.
model,4-3-P86-1038,ak
is desirable . We have developed a
<term>
model
</term>
in which descriptions of
<term>
feature
#16857We have developed amodel in which descriptions of feature structures can be regarded as logical formulas, and interpreted by sets of directed graphs which satisfy them.
other,18-6-P86-1038,ak
<term>
logical model
</term>
in place of a
<term>
denotational semantics
</term>
. This
<term>
logical model
</term>
yields
#16952Our interpretation differs from that of Pereira and Shieber by using a logical model in place of adenotational semantics.
model,12-6-P86-1038,ak
of Pereira and Shieber by using a
<term>
logical model
</term>
in place of a
<term>
denotational semantics
#16946Our interpretation differs from that of Pereira and Shieber by using alogical model in place of a denotational semantics.
tech,5-7-P86-1038,ak
<term>
logical model
</term>
yields a
<term>
calculus of equivalences
</term>
, which can be used to simplify
<term>
#16960This logical model yields acalculus of equivalences, which can be used to simplify formulas.
tech,1-2-P86-1038,ak
linguistic objects
</term>
. Although
<term>
computational algorithms
</term>
for
<term>
unification of feature structures
#16821Althoughcomputational algorithms for unification of feature structures have been worked out in experimental research, these algorithms become quite complicated, and a more precise description of feature structures is desirable.
other,28-5-P86-1038,ak
specified by
<term>
disjunctions
</term>
and
<term>
path values
</term>
embedded within
<term>
disjunctions
#16928This semantics for feature structures extends the ideas of Pereira and Shieber [11], by providing an interpretation for values which are specified by disjunctions andpath values embedded within disjunctions.
tech,15-3-P86-1038,ak
structures
</term>
can be regarded as
<term>
logical formulas
</term>
, and interpreted by sets of
<term>
#16868We have developed a model in which descriptions of feature structures can be regarded aslogical formulas, and interpreted by sets of directed graphs which satisfy them.
other,26-5-P86-1038,ak
for values which are specified by
<term>
disjunctions
</term>
and
<term>
path values
</term>
embedded
#16926This semantics for feature structures extends the ideas of Pereira and Shieber [11], by providing an interpretation for values which are specified bydisjunctions and path values embedded within disjunctions.
other,11-1-P86-1038,ak
of
<term>
features
</term>
to describe
<term>
linguistic objects
</term>
. Although
<term>
computational algorithms
#16817Unification-based grammar formalisms use structures containing sets of features to describelinguistic objects.
tech,4-2-P86-1038,ak
computational algorithms
</term>
for
<term>
unification of feature structures
</term>
have been worked out in experimental
#16824Although computational algorithms forunification of feature structures have been worked out in experimental research, these algorithms become quite complicated, and a more precise description of feature structures is desirable.
tech,8-10-P86-1038,ak
<term>
consistency problem
</term>
for
<term>
formulas
</term>
with disjunctive values is NP-complete
#17009We have shown that the consistency problem forformulas with disjunctive values is NP-complete.
other,3-5-P86-1038,ak
</term>
. This
<term>
semantics
</term>
for
<term>
feature structures
</term>
extends the ideas of Pereira and
#16903This semantics forfeature structures extends the ideas of Pereira and Shieber [11], by providing an interpretation for values which are specified by disjunctions and path values embedded within disjunctions.
other,9-11-P86-1038,ak
complexity
</term>
, we describe how
<term>
disjunctive values
</term>
can be specified in a way which delays
#17025To deal with this complexity, we describe howdisjunctive values can be specified in a way which delays expansion to disjunctive normal form.
tech,11-9-P86-1038,ak
<term>
computational complexity
</term>
of
<term>
unification
</term>
. We have shown that the
<term>
consistency
#16999Our model allows a careful examination of the computational complexity ofunification.
other,28-2-P86-1038,ak
and a more precise description of
<term>
feature structures
</term>
is desirable . We have developed
#16848Although computational algorithms for unification of feature structures have been worked out in experimental research, these algorithms become quite complicated, and a more precise description offeature structures is desirable.
other,9-3-P86-1038,ak
model
</term>
in which descriptions of
<term>
feature structures
</term>
can be regarded as
<term>
logical formulas
#16862We have developed a model in which descriptions offeature structures can be regarded as logical formulas, and interpreted by sets of directed graphs which satisfy them.
tech,23-3-P86-1038,ak
</term>
, and interpreted by sets of
<term>
directed graphs
</term>
which satisfy them . These
<term>
graphs
#16876We have developed a model in which descriptions of feature structures can be regarded as logical formulas, and interpreted by sets ofdirected graphs which satisfy them.