Compositional Semantics - Computational Linguistics and Talking Robots - page 120

7.1.1 C OMPARING REPRESENTATIONS OF THE SUBJECT - VERB RELATION

Phrase Structure Grammar Dependency Grammar DBS

S sleep

sleep

NP VP Julia

Julia

Julia slept

The lines (edges) between the nodes (vertices) have completely different in-
terpretations in the three graphs.
In Phrase Structure Grammar (PSG), the lines specify dominance and prece-
dence . For example, S dominates NP and VP, and NP precedes VP. Thus, the
subject-verb relation is not expressed explicitly in the PSG graph, but must be
deduced from the part of speech interpretation of the nodes NP and VP, and
their configuration in terms of dominance and precedence. 3
In Dependency Grammar (DG), the line between sleep and Julia specifies
Julia as dependent on sleep . This does not distinguish between the subject-
verb and the object-verb relation, equally analyzed as a dependency. 4
In Database Semantics (DBS), there are four semantic relations of structure,
each represented by its own kind of line: (i) “ / ” for the subject-verb relation,

(ii) “ \ ” for the object-verb relation, (iii) “ | ” for the modifier-modified relation,

” for the conjunct-conjunct relation (coordination). 5 Furthermore,
there are three basic parts of speech, which are represented by the letters N for
noun, V for verb, and A for adjective. Given that Julia is an N and sleep is
a V, the DBS graph in 7.1.1 explicitly shows the relation between Julia and
sleep as N

and (iv) “ −

V, i.e., as subject-verb.
Another example is the modifier-modified relation in the similar but some-
what more complex sentence The little girl slept .

/

7.1.2 C OMPARING DETERMINER - ADJECTIVE - NOUN CONSTRUCTIONS

Phrase Structure Grammar Dependency Grammar DBS

S sleep sleep

girl girl

NP VP

DET ADJ N slept

the little little

the little girl