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RE: Enumeration in RDF?

From: Sbodio, Marco Luca <marco.sbodio@hp.com>
Date: Tue, 16 Sep 2003 17:32:19 +0200
Message-ID: <50DFF49E8F8D2344B51FAE9C16854020326F2F@mlnexc01.emea.cpqcorp.net>
To: "Dan Brickley" <danbri@w3.org>, <Art.Barstow@nokia.com>
Cc: <www-rdf-interest@w3.org>

As far as I know OWL has something that helps: owl:cardinality (see http://www.w3.org/TR/2003/CR-owl-ref-20030818/#cardinality-def).
"A restriction containing an owl:cardinality constraint describes a class of all individuals that have exactly N semantically distinct values (individuals or data values) for the property concerned, where N is the value of the cardinality constraint"

This allows you to express cardinality constraints on properties. The OWL Web Ontology Language Reference (see above link) gives an example:

<owl:Restriction>
  <owl:onProperty rdf:resource="#hasParent" />
  <owl:cardinality rdf:datatype="&xsd;nonNegativeInteger">2</owl:cardinality>
</owl:Restriction>

which is a class of individuals that have exactly 2 parents.

So I guess you can express what you want in OWL, but you need to put a constraints on a property (in the above example "#hasParent").

---
Marco Sbodio
while(++$_){print$_,$/if("x"x$_)!~/^(xx+)\1+$/}

> -----Original Message-----
> From: Dan Brickley [mailto:danbri@w3.org]
> Sent: Monday, September 15, 2003 6:04 PM
> To: Art.Barstow@nokia.com
> Cc: www-rdf-interest@w3.org
> Subject: Re: Enumeration in RDF?
> 
> 
> 
> * Art.Barstow@nokia.com <Art.Barstow@nokia.com> [2003-09-15 
> 11:49-0400]
> > 
> > Do the latest RDF specs define a way to do enumeration
> > (e.g. a Bag may contain only 4 strings)?  If so, please
> > send me the pointer.
> 
> http://www.w3.org/TR/rdf-schema/#ch_collectionvocab
> The rdf:List collections mechanism allows the members of a list to be 
> enumeated in a way that makes it clear the whole list has been
> represented. RDF doesn't let you say 'a FooList has only n 
> members'. It
> might be that OWL is applicable to that task; I haven't looked. Now
> would be a great time to send review comments on OWL btw, as 
> they're in
> Candidate Rec phase...
> 
> cheers,
> 
> Dan
> 
> 
Received on Tuesday, 16 September 2003 12:25:56 GMT

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