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[protege-owl] Property restrictions and SWRL
Pierre.Nugues at cs.lth.se
Wed Jan 16 01:55:27 PST 2008
>> If you have an OWL restriction (property_1 hasValue "xxx") attached
> individual_1 you are basically saying that property_1 of individual_1
> must contain the value "xxx". However, no actual value assignment is
> made so the ontology does not contain a value for the property.
I agree that formulated as such its sounds a pretty artificial
example. However, we can imagine that a reasoning process intersects
ranges and results in a singleton that we may want to extract.
>> even if there are individuals that show with the property and
>> value in the Protégé interface.
> The interface will also not show a value for property_1 (unless you
> explicitly assigned one) so I'm not sure what you mean here.
This range value shows in the interface indeed and apparently Protégé
is able to infer. That is why I was not sure if I could get it using
I built a small ontology to exhibit this feature. I also renamed
individual_1 as individual_2 to be consistent with the class names.
In the ontology: http://nlp.cs.lth.se/ontologies/test/restriction_propagation_1.pprj
, I have two classes, Class_1 and Class_2 that contain one individual
each, respectively, individual_1 and individual_2. Class_1 has one
property, property_1. If you click on the Individuals tab in the
Protégé interface, you will see this.
So far, so good... Now I insert a restriction to property_1 using the
hasValue restriction and I set it to individual_2. (Select the
OWLClasses tab, the property views and then the yellow restriction
button). Then, if I click on the Individuals tab, I will see that the
value of property_1 is individual_2.
You have this new ontology here: http://nlp.cs.lth.se/ontologies/test/restriction_propagation_2.pprj
I thought I could get this value using SWRL and I failed. That's why I
asked my question. On the contrary, if this value is asserted, instead
of being inferred, then SWRL returns it.
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