[LC response] To Jeremy Carroll Re: New comment: NegativePropertyAssertions

Dear Jeremy,

Thank you for your comment
     <http://lists.w3.org/Archives/Public/public-owl-comments/2009May/0017.html>
on the OWL 2 Web Ontology Language last call drafts.

The Working Group discussed this topic, in the context of ISSUE-81
<http://www.w3.org/2007/OWL/tracker/issues/81>, and decided
not to use an RDF encoding of the proposed form for negative
property assertions. Although such a mapping has the effect
of reducing the additional vocabulary required for OWL 2 in RDF,
the Working Group believes that this advantage is more than outweighed
by several disadvantages: it obscures the fact that this is a
new feature in OWL 2, impedes the ability to retain ontology structure
in RDF, and would make it more difficult for both users and tools
to specify and detect negative property assertions in RDF-encoded
OWL 2 ontologies. The Working Group does not find any new information
in your proposal that might justify reopening the issue.

Regarding the claim that this is an advanced feature that is unlikely
to be interoperably supported, the Working Group sees no reason to believe
that this is the case. On the contrary, the feature is already supported
by FaCT++, HermiT and Pellet. In addition, Oracle is planning to support
negative property assertions in a soon to be released version of OWL Prime
(see <http://www.w3.org/2007/OWL/wiki/Implementations>), and the
Working Group is also aware of another implementation of OWL 2 RL for
which it has been reported that supporting negative property assertions
was straightforward. Finally, the OWL 2 test suite includes relevant
tests, and these are already being passed by multiple implementations
(see <http://www.w3.org/2007/OWL/wiki/Test_Suite_Status>).

Therefore, the Working Group does not intend to make the change you propose.

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Regards,
Peter F. Patel-Schneider and Michael Schneider
on behalf of the W3C OWL Working Group