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Re: update on I18N review of RDF, OWL

From: Martin Duerst <duerst@w3.org>
Date: Mon, 30 Jun 2003 15:21:36 -0400
Message-Id: <4.2.0.58.J.20030630150906.04b7aa60@localhost>
To: Dan Connolly <connolly@w3.org>
Cc: www-webont-wg@w3.org, w3c-i18n-ig@w3.org

At 09:41 03/06/26 -0500, Dan Connolly wrote:

>On Mon, 2003-06-16 at 17:39, Martin Duerst wrote:
> > Hello Dan,
> >
> > Many thanks for contacting me on this.
> > Please see below for my take on your assumptions.
> > I have copied the I18N IG list, used for technical
> > discussions.
> >
> > At 13:47 03/06/11 -0500, Dan Connolly wrote:
> > >Further to my action to get confirmation from I18N WG
> > >that our last call spec is I18N-happy...
> > >
> > >I talked with Martin in Budapest a couple weeks ago.
> > >
> > >Since then, he collected his thoughts on RDF literals
> > >and such...
> > >
> > >Summary of strings, markup, and language tagging in RDF (resend) Martin
> > >Duerst (Thu, Jun 05 2003)
> > >http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jun/0023.html
> > >
> > >and the RDF Core WG is working thru them.

That didn't show very much, in particular it did not
give any indication that the WebOnt WG thought about the
possibility of equivalence ignoring language.

One interesting discovery, though:

http://lists.w3.org/Archives/Public/www-webont-wg/2002Nov/att-0223/01-dt.html

It has been (deliberately?) left unclear as to whether a plain literal
without a language tag is or is not an xsd:string.

It would be good if this would be resolved the right way
(namely that a plain literal without a language tag is
an xsd:string). If that's not done in RDF, then at least
in OWL (see below).



> > Yes, this is very important for I18N. It's not only my
> > thoughts, it has been confirmed by the WG.
> >
> >
> > >I'm still reasonably confident that OWL doesn't introduce
> > >any I18N issues; that if RDF Core satisfies the I18N WG
> > >(without making changes that we don't like) then I18N WG
> > >will be happy with OWL too.
> >
> > I very much hope that the RDF Core WG will do this, but
> > there are some dependencies. See for example Graham Klyne's
> > mail at
> > http://www.w3.org/mid/5.1.0.14.2.20030606130832.02f79ee8@127.0.0.1,
> > where he mentions that RDF may treat xsd:string and plain
> > literals differently, but something on top of it may treat
> > them as being the same. That 'something' may well be OWL.
> >
> > This ties in with the idea I mentioned in Budapest to have
> > some support in OWL for comparing strings/literals both
> > including and excluding language information. I'm not
> > completely sure OWL is the right place to do that, but
> > how would I otherwise express things such as "this is
> > a functional property if you don't care about the language
> > of the literal". If the webont WG has thought this through,
> > can you point me to the discussion?
>
>Hm... we discussed some perhaps related things under
>the datatypes issue...
>   http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I5.8-Datatypes
>I think we talked about floating-point-equality which
>isn't quite the same as identity... but we didn't
>take the idea very seriously.
>
> >  If not, we should make
> > sure we have had this discussion so that we don't regret
> > a missed opportunity later.
>
>Hmm... I don't know how to make sure that we will.
>I already regret all the missed opportunities since
>around July 2002 when our specs first became available
>for review.
>
> > Also, you mentioned that you wanted to check with us whether
> > we would be okay with the requirements (or, in some case,
> > non-requirements) that OWL had on supporting XML literals
> > and XSD datatypes. Can you tell me where in which spec
> > I can find the details?
>
>The specific required datatypes are documented here...
>
>"OWL tools need only implement the datatypes xsd:integer and
>xsd:string."
>  --
>http://www.w3.org/TR/owl-semantics/syntax.html#owl_built_in_datatypes

What does it mean that an OWL tool implements xsd:string?
That it know the value space and equivalence function of
the datatype (which both are trivial)? Or that it knows
that an xsd:string is the same as a plain literal with the
same character sequence and without any language attached?
I hope it is the later.


Regards,     Martin.


>It relies on an understanding of how the whole formalism
>of RDF and OWL is parameterized by a set of datatypes.
>If you're not familiar with that, the details are in...
>http://www.w3.org/TR/2003/WD-rdf-mt-20030123/#dtype_interp
>
> >
> >
> > Regards,     Martin.
> >
> >
> > >Martin, if you could confirm, tentatively, that would help.
> > >Or should we expect specific review comments on the OWL
> > >specs from the I18N WG?
>
>--
>Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Monday, 30 June 2003 15:22:41 GMT

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