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[protege-owl] How to detect undefined references in rdf:resource
bunsz at gmx.de
Mon Jan 25 10:52:20 PST 2010
you mean for example having a Sign class
a owl:Class .
and a Street class
a owl:Class .
with an object property hasSign
a owl:ObjectProperty ;
rdfs:domain default:Street ;
rdfs:range default:Sign .
and having only one individual:
a default:Street ;
default:hasSign default:Sign_4 .
Sign_4 ist not defined within the ontology ... but the reasoner can
infer that Sign_4 really is a Sign because of the range of the object
property hasSign and therefore will not classify it as an
If the reasoner acts like this it ist fine. The only thing I need is
having a possibility to check for unresolved references like Sign_4,
which actually neighter is defined within this ontology nor in explicit
imported ones. Do you see a chance for me to complete this task with
Thanks in advance,
Am 25.01.2010 17:45, schrieb Timothy Redmond:
> I am not sure why you got that error - it may be that you need to
> include the the class protege:ExternalResource in your ontology. But
> protege:ExternalResource won't quite do what you are looking for
> either; in some cases the Protege parser will figure out the right
> type for the resource and do the right thing.
> Part of the issue is that you are trying to do something that is
> somewhat ill-defined. If you use protege:ExternalResource as your
> guide then in some sense you are looking for rdf:Resources whose type
> cannot be determined by the Protege 3 owl parser. This should not
> happen in OWL DL and the Protege 3 parser will always try to infer the
> type of the resource when it can.
> Bunsz wrote:
>> Thank you again Thomas,
>> I am able to reproduce this, and now I really would like this
>> "protege:ExternalResource" class to be used within SQWRL rules in
>> order to collect all individuals of this type. Unfortunately this
>> rule "protege:ExternalResource(?e) → sqwrl:select(?e)" seems to be
>> syntactically wrong ("Error: Invalid atom name
>> 'protege:ExternalResource'.) For SQWRL this class doesn't seem to be
>> visible. Do you know why? And can this state be changed somehow?
>> Regards, Michael
>> Am 22.01.2010 22:17, schrieb Thomas Russ:
>>> On Jan 20, 2010, at 2:56 PM, Buns wrote:
>>>> Thank you, Thomas,
>>>> but how do I make UntypedResource a visible Class? Do I have to
>>>> define it explicitly?
>>> Actually, it seems to appear in the Protege 3.4.2 automatically
>>> whenever it is needed.
>>> The real name is "protege:ExternalResource".
>>> Attached is a screen shot from my editor showing this for a simple
>>> test ontology defined as:
>>> <owl:ObjectProperty rdf:ID="P"/>
>>> <owl:Thing rdf:ID="i">
>>> <P rdf:resource="#unknown"/>
>>> where there is one otherwise undefined RDF resource named "unknown".
>>>> The background is, I generate an ontology out of an XML-file using
>>>> XSLT in order to use it for verification purposes and for detecting
>>>> kind of inconsistencies. In this context ... can this
>>>> UntypedResource class be used as a dump, where all references to
>>>> undefined resources can be collected?
>>> Well, I would think that when you load the OWL file into Protege any
>>> such external resources would be collected under this class.
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