CODEWITHSUNDEEP
owlontologyprotege
igor.br
igor.br

Reputation: 29

OWL ontology property restriction in equivalentClass

I've defined a class as restriction for a property:

:A rdf:type owl:Class ;
   owl:equivalentClass [ rdf:type owl:Restriction ;
          owl:onProperty :P ;
          owl:someValuesFrom xsd:string
   ] .

and would like to 'reuse' this restriction in another class, whereby I'm using the equivalentClass hierarchy:

:B rdf:type owl:Class ;
   owl:equivalentClass :A.

But then I'm confused with the results shown by Protege: The :B is displayed as equivalentClass to :A (as expected) but as "subClassOf (Anonymous Ancestor)" to "P some xsd:string". I've expected, that :B inherits the property restriction also as equivalentClass.

The subclassing of the property restriction in B instead of equivalent class relation influences the type inferencing of an individual that contains the property P:

:Ind rdf:type owl:NamedIndividual ;     
     :P "p" .

A reasoner (I'm using FACT++) infers that the Ind is of type A because it contains the property P, and of type B - because it is A, and A is equal to B, but not because of the property P.

So, I'd like to ask, why the property restriction is inherited as subClassOf in my example, and if there is a posibility to inherit it as equivalentClass?

Thanks for any hint.

View from A:

view from A

View from B:

view from B

Upvotes: 1

Views: 305

Answers (1)

Antoine Zimmermann
Antoine Zimmermann

Reputation: 5505

Be careful not to confuse Protégé's behaviour with how a reasoner works, or how OWL works. It's possible that, when you apply reasoning in Protégé, Protégé is only asking for what is in the upper hierarchy of the classes. Maybe Protégé does not ask the reasoner what is equivalent. I have noticed that, for several kinds of inferences, Protégé does not display them, even when the reasoners are themselves able to deduce them. I have never put my nose into Protégé's source code, and I have only limited knowledge of how Pellet work, limited theoretical knowledge of HermiT's algorithm, no other knowledge of the code of other reasoners, so I cannot say more.

In any case, you are not misunderstanding how the semantics of OWL works, and this is probably not a bug in the reasoner. It is certainly due to the way Protégé works.

Upvotes: 0

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