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

Stabler - Lx 185/209 2003
(56) Structurally resolved (local) ambiguity
a. Agreement: In simple English clauses, the subject and verb agree, even though the subject and verb can be
arbitrarily far apart:
a. The deer {are, is} in the field
b. The deer, the guide claims, {are, is} in the field
b. Binding: The number of the embedded subject is unspecified in the following sentence:
a. I expect the deer to admire the pond.
But in similar sentences it can be specified by binding relations:
b. I expect the deer to admire {itself,themselves} in the reflecions of the pond.
c. Head movement:
a. i. Have the students take the exam!
ii. Have the students taken the exam?
b. i. Is the block sitting in the box?
ii. Is the block sitting in the box red?
d. A movement:
a. i. The chairi is ti too wobbly for the old lady to sit on it
ii. The chairi is ti too wobbly for the old lady to sit on ti
e. A’ movement:
a. i. Whoi did you help ti to prove that John was unaware that he had been leaking secrets
ii. Whoi did you help ti to prove that John was unaware ti that he had been leaking secrets to ti
(57) English is not glcola(k) for any triggers and any k.
Marcus (1980) pointed out that the ambiguity in, for example, (56c-a), is beyond the ability of an LR(k)
parser, as is easy to see. Since LR is the bottom-up extreme of the GLC lattice, delaying structural
decisions the longest, the fact that English and other human languages are not LR(k) means that they
are not deterministic with k symbols of lookahead for any of the glcola(k) parsers.
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