W3C home > Mailing lists > Public > public-owl-wg@w3.org > January 2009


From: Ivan Herman <ivan@w3.org>
Date: Thu, 22 Jan 2009 10:52:04 +0100
Message-ID: <497841C4.9020301@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>
CC: W3C OWL Working Group <public-owl-wg@w3.org>
HI Bijan,

thanks. This indeed includes my thoughts of yesterday. Actually, reading
it again, I think that we should refer to the RDF spec(s) and not to the
XML ones. Even if the XML specs get updated, the issues you describe
would still be around (at least formally) because, as you say, RDF
normatively refers to Unicode 3. It may be cleaner if OWL refers to RDF
in some open ended fashion so that if RDF is updated at some point in
the future to refer to Unicode 5 (or Unicode 25:-), OWL would be fine.

Having said that, we would have backward compatibility issues in the
sense that we may have ontologies that _today_ are not kosher but would
become so in future. But I guess that should be fine, it fits our open
world view...



Bijan Parsia wrote:
> See: http://www.w3.org/2007/OWL/wiki/LC_Responses/MD1
> Copied below.
> Ivan, please check that I got your point right.
> Cheers,
> Bijan.
> 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)


Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Thursday, 22 January 2009 09:52:42 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:42:08 UTC