[LC Response] to Jan Wielemaker, Re: Triples and OWL2

Dear Jan,

Thank you for your comment

<http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0069.html>
on the OWL 2 Web Ontology Language last call drafts.

Unfortunately, your comment is based on our fault in not conveying the
message clearly enough. The technical fact is that there is no change
between OWL 1 and OWL 2 in terms of the stack you refer to in your comment.

Indeed, Section 2.1 of the Conformance and Test Cases document states
the following:

"Several syntaxes have been defined for OWL 2 ontology documents, some
or all of which could be used by OWL 2 tools for exchanging documents.
However, conformant OWL 2 tools that take ontology documents as input(s)
must accept ontology documents using the RDF/XML serialization [OWL 2
Mapping to RDF Graphs], and conformant OWL 2 tools that publish ontology
documents must, if possible, be able to publish them in the RDF/XML
serialization if asked to do so (e.g., via HTTP content negotiation)."

See:

http://www.w3.org/TR/2008/WD-owl2-test-20081202/#Conformance_.28Normative.29

In other words, the only _required_ exchange syntax among OWL 2 tools is
based on RDF and is RDF/XML (the only small caveat, referred to by the
'if possible' remark in the text, is that there are valid RDF graphs
that cannot be serialized into RDF/XML, eg, if complex URI-s are used
for property IDs). Ie, the situation has _not_ changed compared to OWL 1.

The confusion obviously comes from the fact that the OWL/XML syntax,
which was published as a note[1] for OWL 1, is now on Recommendation
track. OWL/XML for OWL 1 was an optional feature that OWL 1 tools could
implement if they wished to do so. The fact that OWL/XML is now planned
as a recommendation has not changed this.

All that being said, the Working Group recognizes that this issue may
lead to confusion, as witnessed by a number of comments that expressed
the same concerns as yours. The group will take appropriate steps in
conveying this information better by, eg, including multi-syntax formats
into the structural specification and functional-style syntax document,
or making the situation clearer in the appropriate status sections.
Details of these steps are not yet decided at this time.

Please acknowledge receipt of this email to
<mailto:public-owl-comments@w3.org> (replying to this email should
suffice). In your acknowledgment please let us know whether or not you
are satisfied with the working group's response to your comment.

Regards,
Ivan Herman
on behalf of the W3C OWL Working Group

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

-- 

Ivan Herman, W3C Semantic Web Activity Lead
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