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Re: OWL species and subproperties of rdfs:label

From: Bernard Vatant <bernard.vatant@mondeca.com>
Date: Mon, 08 Jan 2007 15:24:21 +0100
Message-ID: <45A25415.8000709@mondeca.com>
To: Dave Reynolds <der@hplb.hpl.hp.com>
Cc: Semantic Web <semantic-web@w3.org>, Tim Berners-Lee <timbl@w3.org>

Hi Dave

Thanks a lot for those clarifications. More below on tools behaviour.

Dave Reynolds a écrit :
> Does SWOOP warn you that this file is OWL/full and so can't be edited 
> safely?
Nope.
>> Loading and saving in Protégé 3.2 yields back
>>
>>  <owl:AnnotationProperty 
>> rdf:about="http://www.example.org/ontology#altName">
>>    <rdfs:subPropertyOf 
>> rdf:resource="http://www.w3.org/2000/01/rdf-schema#label"/>
>>    <rdf:type 
>> rdf:resource="http://www.w3.org/2002/07/owl#DatatypeProperty"/>
>>  </owl:AnnotationProperty>
>>
>> The DatatypeProperty class is added
>
> In OWL/DL AnnotationProperty and DatatypeProperty are disjoint, so 
> even though you are already in OWL/full this seems like a strange way 
> to be behave.
Indeed, more than strange, this is a built-in bug IMO, that has been 
there in various Protégé releases for quite a while. Using GUI as well 
you can't create a simple annotation property.
>> Now if I don't want to presume the property type and just declare
>>
>> <rdf:Property     rdf:about="http://www.example.org/ontology#altName">
>>  <rdfs:subPropertyOf     
>> rdf:resource="http://www.w3.org/2000/01/rdf-schema#label"/>
>> </rdf:Property>
>>
>> SWOOP just ignores this declaration altogether, and the property is 
>> killed when saving.
>
> This is OWL/full, again does SWOOP warn you it might loose OWL/full-isms?
Nothing of the like. SWOOP just seem to *ignore* this declaration.
BTW I just found another strange behaviour of SWOOP. If you declare, 
using the GUI, a property as subproperty of rdfs:label, you have 
rdfs:label itself typed as owl:DatatypeProperty. There is definitely 
something broken here ...
>> Protégé does not show the property in the GUI, but Jena saves it in 
>> the original form.
>
> Yes, Jena can happily read/write OWL/full files and certainly won't 
> loose triples like that.
Indeed, but as long as you don't see them in the GUI, you think 
something is broken, and don't figure what until you look at the code.
>> Well, all that is *very messy* indeed. Looks like that the semantics 
>> of annotation subproperties is defined nowhere, and randomly 
>> implemented in tools. 
>
> Well in a sense the point of Annotation properties is that they don't 
> really carry any semantics, that's why they can be safely used in DL.
I understand that. So according to you, declaration of annotation 
subproperties cannot bear any semantics. So would you recommend to avoid 
such declarations altogether? And in this case, what do I do about Tim's 
request for such declarations to be present in order to make Tabulator 
happy?

>> a:myProperty1      rdfs:subPropertyOf      b:yourProperty2
>> b:yourProperty2       rdf:type      ex:SomePropertyType
>>
>> Does the above entails in RDFS
>>
>> a:myProperty1        rdf:type       ex:SomePropertyType
>>
>> ?? (I guess yes, but maybe I'm wrong)
>
> No. For example, instead of ex:SomePropertyType consider 
> owl:TransitiveProperty then there is no reason why a subProperty of a 
> transitive property should itself be transitive.
OK I see an example

ex:ancestorOf         rdf:type      owl:TransitiveProperty
ex:fatherOf         rdfs:subPropertyOf      ex:ancestorOf

and ex:fatherOf is not a transitive property.

So there is no formal opposition (in OWL-Full) to have a 
owl:DatatypeProperty being a subproperty of rdfs:label, even in an 
ontology where annotation, datatype and object properties are disjoint.
Well I guess I am not the only one to get this wrong, if I judge by the 
way RDF tools handle this. Are such examples documented somewhere?

Bernard

-- 

*Bernard Vatant
*Knowledge Engineering
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Received on Monday, 8 January 2007 14:24:42 UTC

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