W3C home > Mailing lists > Public > semantic-web@w3.org > April 2007

Re: Restrictions on Bags and Seqs content

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Thu, 12 Apr 2007 10:47:58 +0100
Message-ID: <461E004E.7020703@hpl.hp.com>
To: Pat Hayes <phayes@ihmc.us>
CC: Michael Schneider <m_schnei@gmx.de>, rogargon@gmail.com, alanruttenberg@gmail.com, semantic-web@w3.org, public-owl-dev@w3.org

Pat Hayes wrote:

> We really only need one, and encourage everyone to use it. We could make 
> it by replacing the OWL prefix by some other namespace, such as 
> http://www.w3.org/2002/07/owllist#  and calling it 'owllist:'
>> , while there is already a lot of collection vocabulary in RDF, which 
>> they can only use either in a very limited way, like for rdf:Bag and 
>> friends, or not at all, like for rdf:List. Perhaps, it would have been 
>> wiser to not use 'rdf:List' in the OWL-to-RDF mappings (like e.g. for 
>> the argument list of owl:intersectionOf expressions), but instead use 
>> a custom OWLList for this purpose.
> That is what probably should have been done, give that the DL purists 
> insisted on putting that vocabulary out of bounds. But oh well, its too 
> late now.

What about this design for the RDF/XML

<rdf:Description rdf:ID="X">
   rdf:parseType = "eg:Collection"  xmlns:eg="http://example.com/"/>
     <rdf:Description rdf:ID="A"/>
     <rdf:Description rdf:ID="B"/>

<#X> rdf:value _:h .
_h eg:first <#A> .
_h eg:rest _:t .
_:t eg:first <#B> .
_:t eg:rest eg:nil .

i.e. allow eg:Collection as a macro for the collection syntax, 
parameterised over the namespace.

Defect is the use of the QName in the attribute value - permitted but 
discouraged, and it would be the first case in RDF/XML.
Another possibility would be to permit any URI ending in the substring 
"Collection" to behave like that. Or even more oddly, any URI ending in 
Non-NC-Name-Char + "Collection" to behave like that, i.e.

   rdf:parseType= "http://example.com/Collection"
Not OK
   rdf:parseType= "http://example.com/MyCollection"
   rdf:parseType= "http://example.com/My-Collection"


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Received on Thursday, 12 April 2007 09:48:25 UTC

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