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[protege-owl] Inferring using Fact ++

Timothy Redmond tredmond at stanford.edu
Thu Apr 5 15:54:43 PDT 2007


I am not an expert on SPARQL but it seems this is not an open vs.  
closed world question.   The additional result that you wanted does  
follow from the semantics of OWL but the SPARQL query panel doesn't  
apply this inference.  In this regard, some of the criticisms of  
SPARQL for OWL made by Martin in his note

	http://article.gmane.org/gmane.comp.misc.ontology.protege.owl/20247

fit my incomplete understanding of SPARQL and its limitations.

So here is what happened.  When you did the classification of the  
ontology, the inference engine did not insert any property values for  
the Jack into the ontology.  This is not because the inference engine  
could not figure these relationships out - I believe it was because  
Protege did not ask for this information to be inserted.  I tested  
this by making a class called DavidsExtendedFamily which I defined as  
all Person's who are David's father.  When I clicked on "Compute  
Inferred Types" I saw Jack and Peter as both being in  
DavidsExtendedFamily.  So the inference engine does understand this  
inference.

But your classification did not actually change anything either in  
the asserted or inferred ontology.  And then the SPARQL panel did a  
purely syntactic search of the available information and did not find  
the statement Jack is fatherOf David.

Looking on the pellet web site suggests that pellet can be used to do  
SPARQL queries in a way that understands the OWL semantics.

-Timothy




On Apr 5, 2007, at 9:42 AM, Arshan wrote:

> Dear All
>
> I am using Protege 3.2.1 and FaCT++ 1.1.4.
>
> I have defined one class in my taxonomy, called Person. I defined  
> only one
> property called fatherOf which is transitive. I set its Domain and  
> Range as
> Perosn.
>
> Then I defined three individuals:
> Jack
> Peter
> David
>
> Jack is fatherOf Peter
> Peter is fatherOf David.
>
> I click classify taxonomy. Fact++ window opens and runs without  
> problems.
>
> Then I run the following query in SPARQL window:
>
> Prefix kb:  <http://www.testing.org#>
> Select ?m ?n
> Where {?m kb:fatherOf ?n.
>                       }
>
> I see as the result
> Jack fatherof Peter
> Peter fatherof David
>
> But I do not see Jack father of David. Even though father of is  
> transitive and
> I have run the reasoner before querying.
>
> Could you please help me?  I extremely appreciate your help .
>
> Thank you in advance
>
>
>
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