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Literal role restriction by value for specialized template

Posted: Sat Sep 29, 2012 2:07 pm
by vvagr
Part 7 allows creation of specialized template with role restricted by value with a literal (with some instance of one of classes of EXPRESS information representation).

As far as I understand, this possibility was lost in move to Part 8 RDF/OWL representation of templates. I don't see how I can describe restriction with specific value for a literal role of a specialized template.

Is it possible?

Re: Literal role restriction by value for specialized templa

Posted: Mon Oct 01, 2012 1:21 pm
by OnnoPaap
I never considered it to be used but also not to be disallowed.

Why do you think it is not allowed in part 8?

Re: Literal role restriction by value for specialized templa

Posted: Mon Oct 01, 2012 3:45 pm
by HansTeijgeler
At several places a statement is made that in OWL the object (in a predicate) must be either a data literal, a URI reference, or an individual.
That literal only applies to DatatypeProperty. Quoted from W3C:
A datatype property is one of two main categories of properties. It links individuals to data values, and is defined as an instance of the built-in OWL class owl:DatatypeProperty.
<owl:DatatypeProperty rdf:about="#timeStamp">
<rdfs:domain rdf:resource="#Measurement"/>
<rdf:range rdf:resource="&xsd;dateTime"/>
</owl:DatatypeProperty>

That &xsd;dateTime is such a literal.

For all ObjectProperty's we refer to a URI.
Quoted from W3C:
An object property is one of two main categories of properties. It links individuals to individuals, and is defined as an instance of the built-in OWL class owl:ObjectProperty. This defines a property with the restriction that its values should be individuals.
<rdfs:domain rdf:resource="#MotorVehicle"/>
<rdfs:range rdf:resource="#Person"/>
Individuals, like in this example are, in our world, hidden behind a URI instead of using their Name.

Re: Literal role restriction by value for specialized templa

Posted: Tue Oct 02, 2012 11:07 pm
by vvagr
Restriction by value is structured like that, if we use URI of something as a restriction by value:

<owl:Restriction>
<owl:onProperty rdf:resource="http://example.org/tpl#role2" />
<owl:someValuesFrom>
<owl:Class>
<owl:oneOf rdf:parseType="Collection">
<rdf:Description rdf:about="http://rds.posccaesar.org/2008/06/OWL/RDL#RDS8642940" />
</owl:oneOf>
</owl:Class>
</owl:someValuesFrom>
</owl:Restriction>

OWL specs say that
An enumeration is a owl:oneOf element, containing a list of the objects that are its instances.
Datatype values are not instances, therefore I'm assuming that construct

<owl:Restriction>
<owl:onProperty rdf:resource="http://example.org/tpl#role2" />
<owl:someValuesFrom>
<owl:Class>
<owl:oneOf rdf:parseType="Collection">
<xsd:decimal rdf:value="10.5"/>
</owl:oneOf>
</owl:Class>
</owl:someValuesFrom>
</owl:Restriction>

is not allowed.

Am I mistaken?