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Re: OWL S&AS: Translation to RDF Graphs

From: Dan Connolly <connolly@w3.org>
Date: 30 May 2003 13:49:13 -0500
To: Dave Beckett <dave.beckett@bristol.ac.uk>
Cc: public-webont-comments@w3.org
Message-Id: <1054320552.21362.343.camel@dirk.dm93.org>

Thanks for the comment; the WG is discussing how
best to address it. Please stay tuned.

On Fri, 2003-05-09 at 13:33, Dave Beckett wrote:
>   OWL Web Ontology Language Semantics and Abstract Syntax
>   W3C Working Draft 31 March 2003
> 
>   4.1. Translation to RDF Graphs
>   http://www.w3.org/TR/2003/WD-owl-semantics-20030331/mapping.html#4.1
> 
> This transformation table gives the mapping from OWL's abstract
> syntax to RDF triples which means that if you have an OWL ontology in
> the abstract syntax you can write it in OWL's transfer syntax - RDF triples.
> 
> It is however more difficult to see how to go from RDF triples to
> OWL's abstract syntax.  As a semantic web technology, OWL builds on
> RDF triples (and RDF on XML for syntax, URIs etc.) and this form of
> presentation makes it harder to see how to start with RDF and gain
> from OWL vocabulary.
> 
> In detail:
> 
>  1) This presentation may make it hard to see how to transfer OWL -
>    from the transfer syntax (RDF triples) to the OWL abstract syntax.
> 
>    Running the (non-deterministic!) mapping rules backwards seems the
>    only way and is up to each implementer to work out how to do that.
>    Giving this mapping explicitly would be beneficial.  If it depends
>    on the OWL subset in use, this should also be described.  All of
>    this should preferably have and be linked to test cases.
> 
>  2) It is not clear from this mapping what restrictions there are on
>    any existing RDF such that it would already be legal OWL DL or OWL
>    Lite (apart from trying it out with an OWL validator).
> 
>    If the path from RDF to anything but OWL Full is not clear, it
>    seems that it is unlikely that benefits of OWL DL or OWL Lite will
>    be wholly realised.
> 
>  3) The optional and non-deterministic mappings to/from triples are a
>    bad idea that are likely to cause interoperability problems and
>    make the mappings harder.  I urge you to consider removing such
>    non-determinism.
> 
>      I note that several of these are related to having owl:Class and
>      rdfs:Class, a separate issue.
> 
> Thanks
> 
> Dave
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 30 May 2003 14:48:53 GMT

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