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12.7 Designing the Properties 309

In RDF, the domain and range of a property are specified using domain
and range statements. For example, the height of a person would be declared
as follows:

<rdf:Property rdf:ID="personHeight">

<rdfs:domain rdf:resource="#Person"/>

<rdfs:range rdf:resource="xsd:decimal"/>

</rdf:Property>

Similarly, only persons can have or be supervisors, so the supervisor prop-
erty would be declared as follows:

<rdf:Property rdf:ID="supervisor">

<rdfs:domain rdf:resource="#Person"/>

<rdfs:range rdf:resource="#Person"/>

</rdf:Property>

In OWL, one can define domains and ranges in the same way as in RDF.
For example, in the medical chart ontology, each event may be authorized
by a member of the staff. This is specified in OWL as follows:

<owl:ObjectProperty rdf:ID="authorizedBy">

<rdfs:domain rdf:resource="#Event"/>

<rdfs:range rdf:resource="#Staff"/>

</owl:ObjectProperty>

In addition, OWL has the ability to specifylocal rangesrelative to a domain
by means ofowl:someValuesFrom. For example, suppose that admissions may
only be authorized by a doctor. In other words, when an event is in the
Admissionsubclass ofEvent, then the range ofauthorizedByis the sub-
classDoctorofStaff. This is specified in OWL as follows:

<owl:Class rdf:about="#Admission">

<rdfs:subClassOf>

<owl:Restriction>

<owl:onProperty rdf:resource="#authorizedBy"/>

<owl:allValuesFrom rdf:resource="#Doctor"/>

</owl:Restriction>

<rdfs:subClassOf>

</owl:Class>