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Re: How/Why to implement Reification efficiently...

From: Stefan Kokkelink <skokkeli@mathematik.uni-osnabrueck.de>
Date: Thu, 30 Nov 2000 15:58:22 +0100
Message-ID: <3A266B0E.D3A8EB71@mathematik.uni-osnabrueck.de>
To: Gabe Beged-Dov <begeddov@jfinity.com>
CC: www-rdf-interest@w3.org
Gabe Beged-Dov wrote:

<snip />
 > > > As you say, I am proposing that we assume that a conformant
parser
> > > must generate the bags and reified statements. Once we take that step
> > > we can then discuss how to provide straightforward and efficient API
> > > and implementations based on a standard interpretation.
> >
> > I disagree here. In general there is no need to know
> > about the XML structure since the XML serialization
> > is meant for exchanging RDF models (at least that is
> > my point of view ;-).  If you look at the examples of
> > M&S you won't find an RDF graph containing a reification
> > or bagification unless bagID or propertyID are explicitly
> > given. In my opinion a parser SHOULD provide a configuration
> > setting that enforces a bagification for every rdf:Description
> > element (if someone really is interested in the XML structure
> > of the serialization...)
> 
> I am trying to achieve multiple goals with this interpretation of the
> M&S. The goals are:
> 
> - To have a single consistent interpretation of what an
>   RDF processor generates
<snip /> 

Yes, this is overdue. The recommendation was published almost
two years ago, and there is still no such consistent interpretation
what an RDF processor should do.(Please, correct me if I am wrong!)
Besides the above problem there are several other.

Another example: 

<?xml version="1.0"?>
<rdf:RDF
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:s="http://description.org/schema/">
  <rdf:Bag ID="BAG_ID">
     <rdf:li resource="xyz"/>
     <rdf:li resource="abc"/>
  </rdf:Bag>
  <rdf:Description ID="MyID">
   <s:documents>
    <rdf:Description aboutEach="#BAG_ID">
      <s:creator>Karl</s:creator>
    </rdf:Description>
   </s:documents> 
  </rdf:Description>
</rdf:RDF>

If you use one of the four parser available online (hope
I didn't forget one?)
[1],[2],[3],[4], you get four different results. 
This problem has been discussed a while ago (see [5],[6] 
or the question in [7]:Which should we implement?), 
but there is still no decision. In my opinion the
reason for this is that there is no authority who 
could make such a decision (or recommendation).


Stefan

[1] http://swi.psy.uva.nl/projects/SWI-Prolog/packages/sgml/online.html
[2] http://www.w3.org/RDF/Implementations/SiRPAC/
[3] http://www.pro-solutions.com/rdfdemo/
[4] http://zoe.mathematik.Uni-Osnabrueck.DE/RDF/parser.html
[5]
http://lists.w3.org/Archives/Public/www-rdf-interest/2000Aug/0138.html
[6]
http://lists.w3.org/Archives/Public/www-rdf-interest/2000Aug/0153.html
[7]
http://lists.w3.org/Archives/Public/www-rdf-interest/2000Aug/0154.html
Received on Thursday, 30 November 2000 09:59:17 GMT

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