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Re: proposed response to http://lists.w3.org/Archives/Public/public-webont-comments/2003Apr/0029.html

From: Dan Connolly <connolly@w3.org>
Date: 04 Jun 2003 15:21:02 -0500
To: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com>
Cc: www-webont-wg@w3.org
Message-Id: <1054758061.21362.1061.camel@dirk.dm93.org>

On Wed, 2003-06-04 at 13:15, Peter F. Patel-Schneider wrote:
> [Rest of response to 
> 	http://lists.w3.org/Archives/Public/public-webont-comments/2003Apr/0029.html
> ]

This makes sense to me, but I'm not sure I could derive
it from WG discussions.

I'd like to hear from at least one other member of the WG
(either a chair or anybody else) that this is your understanding
of the design.

In particular...

> Here are responses to the remaing questions from your message:
> 
> > (2) The description of the elements of VD is a bit confusing, along with
> > the supported datatype described in section 2. Section 2 says a list of XML
> > Schema datatypes can be used in OWL, ..., *and* OWL also uses rdfs:Literal
> > and can use rdf:XMLLiteral. Section 3.1 says VD contains the URI references
> > of the built-in OWL datatypes and rdfs:Literal. Thus it seems that
> > rdfs:Literal and rdf:XMLLiteral are not built-in OWL datatypes, and
> > rdf:XMLLiteral is not in VD (but can be in D of a datatype theory). Is that
> > right?
> 
> Sections 2 and 3 have been modified to make rdf:XMLLiteral a built-in OWL
> datatype and rdfs:Literal not a built-in OWL datatype.  Data ranges now
> include rdfs:Literal as a special case.  VD is then the built-in OWL
> datatypes plus rdfs:Literal.  This has no real effect on the semantics.
> You can see the revised document at 
> 	http://www-db.research.bell-labs.com/user/pfps/owl/
> 
> > (3) In the definition of datatype theory, it is not clear that what kinds
> > of datatypes can be in the set D. Does it contain only the built-in OWL
> > datatypes, or also their derived datatypes? If it can only consist of
> > built-in OWL datatypes, the datatype theory is quite limited and seems to
> > me not enough in many cases.
> 
> Datatype theories could include more than the built-in datatypes.  However,
> there would have to be a private understanding as to the meaning of these
> datatypes, as OWL has no mechanisms for providing such meaning.

I'd sure be happier if we could quote from our documents some advice
on using datatypes other than integer and string and perhaps other
than XML schema datatypes.

The closest thing I can find is

  6.3 Support for datatype reasoning
  http://www.w3.org/TR/owl-ref/#DatatypeSupport

Hmm...
"Other built-in XML Schema datatypes may be used in OWL Full, but with
caveats described in the OWL Semantics and Abstract Syntax
documentation."
  -- http://www.w3.org/TR/owl-guide/#Datatypes1

what caveats? Mike, can you narrow that link to S&AS down to
a particular section?



Hmm... maybe we could borrow something from
RDF Concepts no RDF primer... no, I don't see anything.

Guus, are you inspired to add something to reference
about use of other datatypes?

> 
> Please let us know whether this satisfactorily addreses the last of your
> comments by replying to the message, ensuring that a copy is sent to
> pubic-webont-comments@w3.org
> 
> 
> Peter F. Patel-Schneider
> Bell Labs Research
> Lucent Technologies
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 4 June 2003 16:20:37 GMT

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