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Re: rdf crystalization

From: Eric van der Vlist <vdv@dyomedea.com>
Date: Thu, 31 Aug 2006 09:05:20 +0200
To: Henry Story <henry.story@bblfish.net>
Cc: Semantic Web <semantic-web@w3.org>
Message-Id: <1157007920.5969.226.camel@localhost.localdomain>
Hi Henry,

Le lundi 28 août 2006 à 16:00 +0200, Henry Story a écrit :
> As it is often useful to have terms to speak about things, I invented  
> "rdf crystalization" to describe what RSS1.1 does
> when it combines a relax-ng with an ontology to create structured rdf/ 
> xml .
> http://blogs.sun.com/bblfish/date/20060828
> RDF is fluid data, but it helps to crystalize it for angle bracket  
> lovers.
> After writing this I thought perhaps I should check if there is  
> already a term for that :-)

This is something that we had already tried to achieve with RSS 1.0 and
we'd discussed at length the opportunity to publish schemas for RSS 1.0.
W3C XML Schema has been rejected quite early because its xs:any
particule couldn't exclude multiple namespaces and would have greatly
reduced the extendability of RSS 1.0. As far as I remember, TREX,
Schematron and Examplotron schemas have been contributed. RELAX NG was
still in its infancy an we've preferred to keep these schemas out of the

The "crystalization" of RSS 1.0 is thus only described in its
specification but it is very real.

I have found the concept of crystalizing RDF is difficult to push in
both XML and RDF worlds: XML eyes have found the RDF tax unbearable and
RDF eyes tend to consider the crystalization of RSS 1.0 as a kind of
non normative guideline for RDF newbies.

I understand both points and reckon that although I am a proponent of
crystalized RDF vocabularies, I would fight any effort to crystalize
XML... Crystalizing RDF is about facilitating the access at both a RDF
and a XML level and that could be transposed to XML to facilitate the
access at both a XML and a text (Unicode) level. This transposition
could be done by providing both a XML schema and a EBNF that would
impose a specific serialization for XML (such as imposing double quotes
to delimit attributes, specific namespace prefixes, ...). This would
have the benefit to lead to XML applications that could be parsed
through regular expressions!

I find it hard to explain why I think that crystalizing XML is a bad
idea while crystalizing RDF is a good one but I try to pursue this
principle when I work with RDf and:

      * My XML/RDF QBE syntax
        (http://www.idealliance.org/papers/extreme/Proceedings/html/2005/Vlist01/EML2005Vlist01.html) is crystalized. 
      * My main contribution to the INSEE geographical ontology
        (http://rdf.insee.fr/geo/) has been to make sure that it
        crystalizes nicely. If you look at one of the instance documents
        such as http://rdf.insee.fr/geo/cantons-01-2003.rdf you'll see
        that we've done a very good job to keep the "RDF tax" as low as
        possible and I plan to write a RELAX NG schema to describe this

Thanks for giving a name to this principle!

> Henry
> Home page: http://bblfish.net/
> Sun Blog: http://blogs.sun.com/bblfish/
> Foaf name: http://bblfish.net/people/henry/card#me
GPG-PGP: 2A528005
Freelance consulting and training.
Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
(ISO) RELAX NG   ISBN:0-596-00421-4 http://oreilly.com/catalog/relax
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema

Received on Thursday, 31 August 2006 07:05:33 UTC

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