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Re: OWL equivalentClass question

From: David Booth <david@dbooth.org>
Date: Fri, 13 Jul 2012 10:30:12 -0400
To: Michael Schneider <schneid@fzi.de>
Cc: semantic-web@w3.org, nathan@webr3.org
Message-ID: <1342189812.3555.29783.camel@dbooth-laptop>
On Fri, 2012-07-13 at 15:05 +0200, Michael Schneider wrote:
> [Hrmph, I found another error in my first post. So forget
> all my previous posts, here is complete rewrite with the
> errors being fixed.]
> 
> Hi Nathan!
> 
> In the context of datatypes and data ranges (including
> datatype restrictions, as you use them in your examples),
> the term "owl:equivalentClass" is used in the RDF syntax
> of OWL 2 for stating /datatype definitions/; see [1] for
> the specification of datatype definitions, and Table 16
> in [2] for the reverse RDF mapping from the RDF encoding
> of datatype definitions to their OWL 2 functional syntax
> counterparts.
> 
> Further, from the last entry of Table 12 in [2], you can
> see that the RDF encoding of /datatype restrictions/ is
> only defined for blank nodes (as in your first example),
> so the mapping of datatype definitions does not apply if
> a URI is used instead (as in your second example).

So if the blank nodes are skolemized, 
http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#section-skolemization 
then the OWL 2 mapping breaks?  This sounds like a bug in the mapping
algorithm.

David

> 
> Hence, only the first of your two examples is syntactically
> valid in OWL 2 DL, and its meaning is, as you certainly
> intended, to define a name (URI) for the given datatype
> restriction.
> 
> [1]
> <http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/#Datatype_Definitions>
> [2] <http://www.w3.org/TR/2009/REC-owl2-mapping-to-rdf-20091027/>
> 
> Best,
> Michael
> 
> > Am 13.07.2012 14:17, schrieb Nathan:
> >> Hi all,
> >>
> >> I'm looking to define a few Datatype's, and wondered why
> >> owl:equivalentClass is used for all complex types in the
> >> primer/documentation.
> >>
> >> For example what's the difference between:
> >>
> >> :personAge  owl:equivalentClass
> >>    [ rdf:type  rdfs:Datatype;
> >>      owl:onDatatype  xsd:integer;
> >>      owl:withRestrictions (
> >>       [ xsd:minInclusive  "0"^^xsd:integer ]
> >>       [ xsd:maxInclusive  "150"^^xsd:integer ]
> >>      )
> >>    ] .
> >>
> >> and:
> >>
> >> :personAge rdf:type  rdfs:Datatype;
> >>    owl:onDatatype  xsd:integer;
> >>    owl:withRestrictions (
> >>     [ xsd:minInclusive  "0"^^xsd:integer ]
> >>     [ xsd:maxInclusive  "150"^^xsd:integer ]
> >>    ) .
> >>
> >> Is the second example valid, any reasons not to do it, what am I missing
> >> here?
> >>
> >> TIA,
> >>
> >> Nathan
> >>
> >
> 

-- 
David Booth, Ph.D.
http://dbooth.org/

Opinions expressed herein are those of the author and do not necessarily
reflect those of his employer.
Received on Friday, 13 July 2012 14:30:47 UTC

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