Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
3 Extensions of the top-down recognizer
3.1 Unification grammars
(1) How should agreement relations be captured in a grammar? We actually already have a powerful mechanism
available for this: instead of “propositional grammars” we can use “predicate grammars” where
the arguments to the predicates can define subcategorizing features of each category.
We explore this idea here, since it is quite widely used, before considering the idea from transformational
grammar that agreement markers are heads of their own categories (Pollock 1994, Sportiche 1998, many
others).
(2) Consider the following grammar:
% g2.pl
:- op(1200,xfx,:˜).
ip :˜ [dp(Per,Num), vp(Per,Num)].
dp(1,s) :˜ [’I’]. dp(2,s) :˜ [you]. dp(3,s) :˜ [it].
dp(3,s) :˜ [she].
dp(3,s) :˜ [he].
dp(3,Num) :˜ [d1(Num)]. d1(Num) :˜ [d0(Num), np(Num)]. d0(_Num) :˜ [the].
d0(p) :˜ [most]. d0(s) :˜ [every]. d0(p) :˜ [few].
np(Num) :˜ [n1(Num)]. n1(Num) :˜ [n0(Num)]. n0(s) :˜ [penguin].
n0(p) :˜ [penguins].
vp(Per,Num) :˜ [v1(Per,Num)]. v1(Per,Num) :˜ [v0(Per,Num)]. v0(1,s) :˜ [sing].
v0(2,s) :˜ [sing].
v0(3,s) :˜ [sings].
v0(3,p) :˜ [sing].
With this grammar g2.pl I produced the following session:
1 ?- [td],[g2].
td compiled, 0.00 sec, 1,116 bytes.
g2 compiled, 0.01 sec, 2,860 bytes.
Yes
2 ?- [every,penguin,sings] ?˜ [ip].
Yes
3 ?- [every,penguins,sing] ?˜ [ip].
No
4 ?- [it,sing] ?˜ [ip].
No
5 ?- [it,sings] ?˜ [ip].
Yes
6 ?- [the,penguin,sings] ?˜ [ip].
Yes
7 ?- [the,penguin,sing] ?˜ [ip].
No
8 ?- [the,penguins,sings] ?˜ [ip].
No
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