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Re: LANG: number range expressions

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Thu, 2 May 2002 21:27:45 +0100
Message-ID: <15569.41281.19413.253886@merlin.oaklands.net>
To: Dan Connolly <connolly@w3.org>
Cc: Ziv Hellman <ziv@unicorn.com>, www-webont-wg@w3.org
On May 2, Dan Connolly writes:
> On Thu, 2002-05-02 at 12:46, Ziv Hellman wrote:
> > I was recently looking through some DAML+OIL documentation and I noticed
> > that in order to, for example, constrain the property 'age' of a class
> > Adult to being 17 or over, one needs the following syntax.
> > 
> > <daml:Class rdf:ID="Adult">
> >  <daml:intersectionOf rdf:parseType="daml:collection">
> >  <daml:Class rdf:about="#Person"/>
> >     <daml:Restriction>
> >       <daml:onProperty rdf:resource="#age"/>
> >       <daml:hasClass 
> > 	
> > rdf:resource="http://www.daml.org/2001/03/daml+oil-ex-dt#over17"/>
> >     </daml:Restriction>
> >   </daml:intersectionOf>
> > </daml:Class>
> > 
> > <xsd:simpleType name="over17">
> >   <!-- over17 is an XMLS datatype based on decimal -->
> >   <!-- with the added restriction that values must be >= 17 -->
> >   <xsd:restriction base="xsd:decimal">
> >   <xsd:minInclusive value="17"/>
> >   </xsd:restriction>
> > </xsd:simpleType>
> 
> In the course of the design of DAML+OIL, I suggested incorporating
> XML Schema datatype facets into RDF/DAML+OIL; it might look
> like this...
> 
> <rdf:RDF
>     xmlns:dt="http://www.w3.org/2001/XMLSchema#"
>     xmlns:ex="http://example/vocab#"
>     xmlns:ont="http://www.daml.org/2001/03/daml+oil#"
>     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>     xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#">
> 
>     <rdfs:Class rdf:about="http://example/vocab#Adult">
>         <ont:intersectionOf rdf:parseType="ont:collection">
>           <rdfs:Class rdf:about="http://example/vocab#Person"/>
>           <ont:Restriction>
>             <ont:hasClass rdf:parseType="Resource">
>               <ont:intersectionOf rdf:parseType="ont:collection">
>                 <rdfs:Class
> rdf:resource="http://www.w3.org/2001/XMLSchema#decimal"/>
>                 <rdfs:Class>
>                   <dt:minInclusive>17</dt:minInclusive>
>                 </rdfs:Class>
>               </ont:intersectionOf>
>             </ont:hasClass>
>             <ont:onProperty rdf:resource="http://example/vocab#age"/>
>           </ont:Restriction>
>         </ont:intersectionOf>
>     </rdfs:Class>
> </rdf:RDF>
> 
> or something like that.
> 
> But the group decided to keep the datatypes and the rest of the universe
> of discourse separate, and this was one of the related consequences.

Syntax and semantics are separate issues and completely orthogonal in
this case: we could keep the current syntax but change the semantics
to have a single universe OR change the syntax to some "in-line"
format without changing the semantics OR change both (OR change
neither).

Ian

> 
> I have raised the issue of splitting datatypes out...
> http://www.w3.org/2001/sw/WebOnt/webont-issues.html#5.1-Uniform-treatment-of-literal/data-values
> 
> But maybe this is worth a separate issue.
> 
> In the RDF Core WG's discussions about datatypes, I recently
> suggested we include facets in the design...
> 
>   # user-defined datatype (facet) support needed?
>   Dan Connolly (Tue, Apr 30 2002) 
>   http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Apr/0547.html
> 
> 
> 
> [...]
> > Will OWL inherit this type of behaviout from DAML+OIL?
> 
> Unless somebody raises an issue and we decide to resolve
> the issue by changing it, yes.
> 
> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> 
Received on Thursday, 2 May 2002 16:31:00 GMT

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