Grammatical Formalisms
Postgraduate course «Technoglossia»
Stella Markantonatou
Athens, October 2012
LECTURE 4
Unification. FS, Unification and CFPSG
CONTENTS
1.
2.
3.
Unification ................................................................................................................. 1
Unification and PS Grammar .................................................................................... 2
References ................................................................................................................. 4
1. Unification
(1)
[1]
Number
Gender
Case
[3]
pl
neut
nom V acc
Number
Gender
Case
Person
pl
neut
nom V acc
3rd
[2]
Number
Gender
Case
Person
pl
neut
nom V acc
3rd
Consider (1). Information comes from the lexicon where the linguistic objects are words
such as Determiners and Nouns (among others). We can model information flow with
phrase structure formation as follows:, the information related with linguistic objects (such
as words) is unified and the result of this unification is the information related with the new
linguistic 0bject (such as a new phrase) formed. As we use Feature Structures to represent
information, we talk about the Unification operation that applies on FS to yield new
ones. In (1), the FS [1] and [2] unify to yield [3]. [3] is the unification of [1] and [2].
Let us consider [3] more carefully. [3] contains all the information in its parent FS [1] and [2].
It is important to note that in (1) unification succeeded because the information in [1] and
[2] is compatible. If it was incompatible, unification would have failed.
Definition 1
So, the Unification C of two FS A and B is
o An FS
o That contains all the attributes occurring in A and B
o That contains all reentrancies occurring in A and B
o The values of the attributes of C is the unification of the values of the attributes of A
and B
The unification of two values is possible if
o They are identical constants
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Grammatical Formalisms
Postgraduate course «Technoglossia»
Stella Markantonatou
Athens, October 2012
o They are FS that can unify
Exercise 1: Use Definition 1 to explain why [3] is the unification of [1] and [2].
Exercise 2: Is the unification of [14] and [15] possible? Why? Exemplify the situation with
appropriate linguistic objects.
[14]
Number
Gender
Case
pl
neut
nom V acc
[15]
Number
Gender
Case
Person
sg
fem
gen
3rd
Exercise 3: [18] is the unification of [16] and [17]. Would [19] unify with [17]?
[16] Alpha alpha
[17] Kappa kappa
Beta Gamma
gamma
Beta Zeta zeta
Delta
delta
[18]
[19]
Alpha alpha
Kappa kappa
Beta Gamma
Delta
Zeta
Alpha
Beta
Kappa
1
gamma
delta
zeta
alpha
Gamma gamma
Delta
delta
1
2. Unification and PS Grammar
[20]
Cat
v
Pred αγαπώ
Agr
1
Case nom
Subj
Cat
n
Pred παιδιά
DET +
Agr
1
Obj
Cat
Pred
DET
n
τηγανίτες
+
2
Grammatical Formalisms
Postgraduate course «Technoglossia»
Stella Markantonatou
Athens, October 2012
Αgr
2
Case acc
Consider [20]. This is an FS representation of the sentence τα παιδιά αγαπούν τις
τηγανίτες. [20] in some ways is similar to FS sentence representations we have seen so far
and in some other, very important ways, it is different. First of all, [20] has a feature Pred
that takes constants as values. Second, it has features such as Subj(ect) and Obj(ect) which
we have not so far used with our PS grammars. Now, subject and object are names of
functions that phrasal constituents fulfil in a sentence. Thus, these names are not on a par
with phrasal constituent names such as np, vp etc. These names do not appear as values of
the feature Cat in [20]. The Cat values are those of the corresponding lexical heads (n, v,
etc).
In [20], subject-verb agreement has been modelled with reentrancies plus a constraint, that
of the nominative case. A similar constraint specifies that the object should be in the
accusative case.
Let us now assume the PS rule (2)
(2) S NP V NP
Let us now consider the kind of lexical entries that would yield [20] on the basis of (2). The
verb would contribute a structure like (3).
(3)
Cat
Pred
Agr
v
αγαπώ
1
Case nom
Subj
Cat
Agr
n
1
Obj
Cat
Αgr
n
2
Case acc
2
NPs would be built with rule (4)
(4) NP  Det N
The nouns would have lexical entries of the sort of (5)
(5)
Cat n
Pred παιδί
Agr Case Case
Num Num
Pers Pers
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Grammatical Formalisms
Postgraduate course «Technoglossia»
Stella Markantonatou
Athens, October 2012
Gen
Gen
The definite determiners would have lexical entries of the sort of (6)
(6)
DET +
Agr Case Case
Num Num
Gen Gen
The italics indicate that these are values of the corresponding type, for instance, Num can
have values of the sort sg, pl, dual. These values may be constants or disjunctive values such
as sg V pl.
Unification would check correct agreement and would yield the right NPs in the spirit of (4).
Then, the NPs would unify with (3) in the spirit of (2). Notice that unification would
succeed independently of word order in both np-formation (4) and s-formation (2). So,
while word order is explicitly specified in PS rules such as (2) and (4), a large quantity of
information about the phrases can be checked and encoded independently of word order.
This means that all these word orders carry the same basic information --- and this is rather
intuitive and that they are all assigned the same representation. These are basic ideas of
LFG and we will come back to them quite soon!!!
Exercise 4: Write the lexical entries for the phrases
Έφυγε το σημαντικό μήνυμα.
Πρέπει να φύγω.
Give the PS rules that yield them and explain how well-formedness is checked with
unification.
3. References
Mary Dalrymple. 2002. Syntax and Semantics 34: Lexical Functional Grammar. Academic
Press
Ivan A. Sag and Thomas Wasow. Syntactic Theory: A Formal Introduction. CSLI Publications,
Leland
Stanford
Junior
University
(σημειώσεις
(http://hpsg.stanford.edu/book/slides/index.html).
Stuart M. Shieber. 1986. An Introduction to Unification Based Approaches to Grammar.
Chicago: Chicago University Press.
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