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Comments from RDFCore on S+AS

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Fri, 09 May 2003 18:02:44 +0100
Message-Id: <>
To: public-webont-comments@w3.org

The RDFCore WG has me to forward the comments below on their behalf.  Other 
comments, on behalf of RDFCore will be sent in separate messages.




RDFCore notes the a consequence of the rules for owl:equivalentClass is
that distinguishing OWL DL from OWL Full has complexity NP complete and
suggests WEBONT investigate whether this complexity can be reduced.

We note from the RDF semantics document

Specifications of such syntactically restricted semantic extensions MUST 
include a specification of their syntactic conditions which are sufficient 
to enable software to distinguish unambiguously those RDF graphs to which 
the extended semantic conditions apply.



RDFCore are concerned that restrictions placed on b-nodes will limit the
applicability of OWL DL to an unnecessarily restricted subset of RDF
instance data, for which no such restrictions apply.

For example, consider the use case in:


If bNodes can only be used as the object of a single triple, they lose most
of their value as a construct in the language. As does rdf:nodeID for that

     <mbox rdf:resource="mailto:danbri@w3.org"/>

    <homepage rdf:resource="http://www.w3.org/People/DanBri/"/>

...is OK in OWL, but if we add in an rdf:nodeID on the two Person elements
to express that they serialize descriptions of the same (un-named) resource,
we're in trouble? Ouch. That breaks most of my uses of RDF, and a lot of
deployed FOAF documents.

Specifically we request, that in Owl DL and Owl lite:

   a) that a b-node representing an individual may be the object of more
than one triple
   b) that cycles of b-nodes representing individuals be allowed.

Received on Friday, 9 May 2003 13:02:54 UTC

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