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OWL S&AS: Translation to RDF Graphs

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Fri, 09 May 2003 19:33:00 +0100
To: public-webont-comments@w3.org
Message-ID: <10559.1052505180@hoth.ilrt.bris.ac.uk>


  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
Received on Friday, 9 May 2003 14:36:27 GMT

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