LC Responses/MD1

To: duerst@it.aoyama.ac.jp
CC: public-owl-comments@w3.org
Subject: [LC response] To Martin Duerst

Dear Martin,

Thank you for your comment
     <http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0003.html>
on the OWL 2 Web Ontology Language last call drafts.

NOTE COMMENT LINK IS SORTA WRONG! SANDRO...CAN YOU GIVE DIRECT LINK?!?

The hardcoded references to Unicode 3.0 were inherited from RDF and RDF/XML. Upon investigation, the WG decided that we did not need to and should not add more "point of update" for Unicode (or XML) references in spite of our dependancy on RDF and RDF/XML. Accordingly, we have shifted to a generic reference, as described in:

        <http://www.w3.org/TR/charmod/#sec-RefUnicode>

The reference text is available at:

        <http://www.w3.org/2007/OWL/wiki/References/unicode>

We have added text to our conformance document describing the situtation. We also filed a bug report against the RDF specs:

        <http://lists.w3.org/Archives/Public/www-rdf-comments/2009JanMar/0001.html

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,
Bijan Parsia
on behalf of the W3C OWL Working Group

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> Private communication with Sandro yields: see http://www.w3.org/TR/charmod/#sec-RefUnicode.

The basic reason is that RDF/XML and XML are (by and large) tied to older versions of Unicode, and we're following them.

We can:

• Stick with 3.0.
• Update to 5.0.
• Let it be extensible, adapting to the "latest version".

Where it matters:

• Identifiers, i.e., what counts as a legal spelling for IRIs
• String/plain literals (for obvious reasons).

Possible impact:

• Semantically -- new characters mean that counts of strings might change, which mean that some unsatisfiabilities would change.
• Syntactically -- the structural model might be able to contain IRIs and strings which it cannot serialize into some syntaxes (because, for example, they were defined against Unicode 3, or 5). This seems to be the case for RDF/XML and XML
• http://www.w3.org/TR/rdf-syntax-grammar/#section-Terminology
• http://www.w3.org/TR/REC-xml/#Unicode

Note that "release 5" of XML changed the reference from 3 to 5, but with a lot of controversy. RDF seems to normatively reference 3.

• http://www.w3.org/TR/rdf-concepts/#section-Normative-References
• http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210/#section-References

Since it's not just the RDF/XML syntax, but the RDF model, it may be the case that we would have ontologies that are not representable in the RDF Model.

Ivan's thought was that we could be "open ended" with respect to Unicode (i.e., not reference a version) but delegate to other specs (i.e., RDF or XML). That way, we would be, at least, in synch with them if they should update (as XML is already trying to).

(Jeremy would be a good person to ask about it.)

BijanParsia 20:16, 21 January 2009 (UTC)

> Draft response discussion