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Presentation Syntax - why?

From: Danny Ayers <danny666@virgilio.it>
Date: Tue, 17 Jun 2003 11:47:39 +0200
To: <public-webont-comments@w3.org>
Message-ID: <BKELLDAGKABIOCHDFDBPIECLDBAA.danny666@virgilio.it>

At times it seems that the real activity of the WG can only be seen like the
structure of DNA was through X-Rays. A strange crystal that has just
appeared on a plate is the OWL Web Ontology Language XML Presentation Syntax
Note [1]. There doesn't appear to be any documentation of the role of
languages like this, and it's hard to place it in context.

Reading the documentation for OWL it is clear that the intention was for it
to be a layer directly on top of RDF and RDFS, yet what the AS&S describes
needs a significant translation from OWL->RDF [2] and is currently only
mappable in the RDF->OWL direction through quite a convoluted procedure [3].

The impression this gives is that AS&S has in large part been constructed as
an entirely new language, with the RDF(S) considerations being retrofitted
late in the day. How much truth there is in this isn't really important,
what is important is that the roadmap has become smudged.

I believe significant clarification is required around certain issues, in
particular those that lead to the Presentation Syntax. It appears that this
is a concrete representation of the AS&S, but for what purpose? If the
underlying model used by the AS&S is compatible with the RDF graph/triples
model, then why not use RDF/XML? Or is there such an air gap between the RDF
and OWL layers, that the OWL can fly free with it's own model, syntax and
serialization?

On a practical level, the question is simple if a developer wishes to build
a Semantic Web application, where do they start? If they start with RDF now,
will they need a rework to be able to include OWL features without the
struggle of [3]? Or if they start with OWL AS&S will they lose the
compatibility with existing RDF data without building tools to carry out the
transformations of [2]?

I realise this is relatively early days for OWL, it just seems from what's
being delivered that sometimes there are triples being asserted that are
dark for anyone outside of the WG.

Cheers,
Danny.

[1] http://www.w3.org/TR/2003/NOTE-owl-xmlsyntax-20030611/

[2] http://www.w3.org/TR/2003/WD-owl-semantics-20030331/mapping.html#4.1

[3] http://wonderweb.semanticweb.org/owl/parsing.shtml

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http://dannyayers.com
Received on Tuesday, 17 June 2003 05:51:08 GMT

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