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Communicating with Databases in Natural Language - Wallace M.

Wallace M. Communicating with Databases in Natural Language - Ellis Horwood Limited, 1985. - 170 p.
Download (direct link): comumunicatingwthisdatabase1985.djvu
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104 SEMANTICS
[Ch
candidate Attribute Domain
candidate party election vote person party election vote
Fig 5.16 - The ‘candidate’ relation.
the domains ‘vote’ and ‘party’ both match attributes of the ‘candidate’ relation. The core qualifier for the noun phrase is:
candidate (vote=X, par ty=Y).
The natural language function which interprets “the liberal vote” is thus:
‘liberal’ is funct(Y,
the-1 -qual(X, candidate (vote=X, par ty=Y)))
(2) “The 1974 and 1975 elections inWorthing” This has headnoun, “elections”, which is an entity, ‘election’ The noun is plural so, in the absence of an explicit count, the formal count is left variable, ‘the-N-election , .’ The modifiers are, firstly “1974 and 1975”, which has semantic category domain (date), and interpretation;
‘1974’& ‘1975’,
and secondly “in Worthing”, which has semantic category ‘domain(constituency)’ and is interpreted as:
‘worthing’.
Now ‘election’ is the entity relation:
election Attribute Domain
id constituency date election constituency date
Fig, 5.1'7 - The ‘election’relation.
Thus the core qualifier is:
election(id=X,date=Yl,constituency=Y2),
Finally the whole natural language function is:
‘1974’&‘1975’is qual(Yl,
‘worthing’ is qual (Y2,
the-N-qual(X,election(id=X,date=Yl, constituency= Y2))))
5]
SEMANTICS 105
4.4.2 Postqualification
If an initial noun phrase has interpretation ‘Det-N-qual(X,Quail)’ and a relative clause has interpretation, ‘Qual2[X]\ then the interpretation of the whole (noun phrase + qualifier) is:
‘Det-N-qual(X, Quail & Qual2[X]).
A relative clause is a sentence with a ‘trace’ in it, thus in the example,
“The seat which Smith holds”,
the relative clause is the sentence;
“Smith holds [constituency: X]”,
The trace is a hole where something appears only implicitly Generally a trace occurs when the missing item has already appeared earlier in the sentence (e g Pereira’s ‘Extraposition Grammars’, [34]), The relative pronoun, “which”, represents the thing in the hole — ‘constituency’. In our example database, this sentence is interpreted as:
‘smith’ is qual(Y,constituency(id=X,membei=Y))
“The seat” is just, 4he-l-qual(X,tiue)’, so the whole noun phrase “The seat which Smith holds”, is interpreted as:
the-l-qual(X,true &
‘smith’ is qual(Y,
constituency (id=X,member=Y))),
A relative clause can also involve postmodification via the relative pionoun, “whose”, (or “where” as in many query languages) Consider the phrase:
“The seat whose member is 54”
The relative clause, “whose member is 54”, has two parts:
(1) “[person:Xl] is 54”.
This is the postqualification and has the interpretation:
‘54’ is qual(Yl,person(age=Yl,id=Xl))
(2) “Whose member” (oi “the member foi [constituency:X2] ”)
This is the postmodification and has the interpretation:
X2 is funct(Y2,
the-l-qual(Xl, constituency(id=Y2,member =X1))),
The whole noun phrase “The seat whole member is 54” is as shown in Fig, 5 18,
106 SEMANTICS
[Ch
the-l-qual(X2,
true
&
X2 is funct(Y2,
the-l-qual(Xl, constituency (id=Y2, member=Xl))) is qual(Y3, ‘54’ is qual(Yl,person(age=Yl,id=Y3))))
Fig 5.18 - The inter pi eta tion of “The seat whose member is 54”
5. THE VERB “TO BE”
The verb “to be” is three ways ambiguous. The first two interpretations are very similar. They are illustrated in the sentences:
“Who is Mary?”
“Who are James and John?”
In English the meaning of “is” and “are” in their respective sentences is identical. The thing, or things, referred to by the subject of the sentence is the same as the reference of the grammatical object. Both “is” and “are” can be treated by case analysis according to the dictionary entries:
(1) rel(id), {logical-subject= subj, logical-object= obj},
(2) rel(equal),{logical-subject= subj, logical-object= obj)
The relations ‘id’ and ‘equal’ are not part of the database, but they are built into D&Qs (see Chapter 4, section 2 1) These two relations require a different domain check from usual because, although any domain matches the subject and object, there is a constraint that the domains associated with the verb modifiers, logical-subject and logical-object, must match each other.
The other interpretation of the verb “to be” has only one verb modifier, the logical-subject. Examples are:
“Worthing is in the south”
“How old is Smith'!”
(The logical-subject is underlined in each case.)
The predicate is a noun modifier list, and it interacts with the semantic category of the logical subject to yield a formal qualifier If ‘Desc’ is the interpretation of the logical subject, and the predicate yields ‘Qual’, then the interpretation of the sentence is, ‘Desc is qual(Y,Qual)’
For example, “Which constituency is in the south” has a logical subject “which constituency” This is interpreted as:
what-l-qual(X,true)
5]
SEMANTICS 107
The headnoun is an entity, ‘constituency’, and the predicate contains the single modifier, ‘south’. It yields the qualifier:
‘south’ is qual(Y2,
constituency (id=Y l,area=Y2))
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