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[protege-owl] Property restrictions and SWRL

Pierre Nugues Pierre.Nugues at cs.lth.se
Wed Jan 16 01:55:27 PST 2008


Martin,

>> If you have an OWL restriction (property_1 hasValue "xxx") attached  
>> to
> 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  
SWRL rules.
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.

Pierre


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