Information Technology Reference
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WSML-Full.
The logical syntax of WSML-Full is equivalent to the general
logical expression syntax of WSML and allows the full expressiveness of
all other WSML variants.
The separation between conceptual and logical modeling allows a gentle
learning curve for nonexperts, since the conceptual syntax does not require
expert knowledge in logical modeling, whereas complex logical expressions
require more familiarity and training with the language. Thus, WSML al-
lows the modeling of various aspects of Web services on a conceptual level,
while still offering the full expressive power of the logic underlying the chosen
WSML variant. Part of the conceptual syntax for ontologies has an equiva-
lence in the logical syntax. This correspondence is used to define the semantics
of the conceptual syntax. Note that since only parts of the conceptual syntax
are mapped to the logical syntax, only part of the conceptual syntax has a
semantics in the logical language for ontologies. For example, nonfunctional
properties are not translated (hence the name “nonfunctional”). The transla-
tion between the conceptual and the logical syntax is sketched in Table 7.2.
Table 7.2.
Translating the conceptual to the logical syntax
Conceptual
Logical
concept
A subConcepOf B
A
subConceptOf
B.
A[B
ofType
C].
!
−
?x
memberOf
A
and
?x[B
hasValue
?y, B
hasValue
?z]
and
?y != ?z.
concept
AB
ofType
C A[B
ofType
C].
relation
A/n
subRelationOf
B A(x
1
,...,x
n
)
implies
B(x
1
,...,x
n
)
instance
A
memberOf
B
C
hasValue
D
concept
A
B
ofType
(0 1) C
A
memberOf
B.
A[C
hasValue
D].
7.3 WSML Semantics
The semantics of WSML ontologies is defined through a mapping between the
WSML logical syntax and the formalism which underlies the variant. WSML-
Core and WSML-DL logical expressions are mapped to first-order predicate
logic (FOPL). The restrictions on the WSML syntax for these variants ensure
that the expressions stay inside the expressiveness of the
description
logic. The semantics of WSML-Flight and WSML-Rule is defined through a
mapping to F-Logic programming [72, Appendix A].
In order to facilitate the mapping between a WSML variant and the un-
derlying logic, the WSML ontology is first transformed to a set of normalized
logical expressions, according to Table 7.2. Then, this normalized set of logical
expressions is mapped to the logic using a mapping function
π
. Finally, satis-
fiability and entailment are defined with respect to this transformed WSML
ontology.
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