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Re: Yet more XSD/RDF

From: Dan Connolly <connolly@w3.org>
Date: 26 Nov 2002 09:16:53 -0600
To: Jeremy Carroll <jjc@hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
Message-Id: <1038323813.5180.1558.camel@dirk>

On Tue, 2002-11-26 at 08:51, Jeremy Carroll wrote:
> 
> 
> I completed my investigation doc.
> 
> See:
> 
> http://lists.w3.org/Archives/Public/www-archive/2002Nov/att-0092/02-index.ht
> ml
> 
> More important points are:
> 
> - there are issues with the XSD document: most is clear, a small part is
> clear in the opposite direction.

Yes, clearly this text is inconsistent with other parts of the
spec:

|  Note that a consequence of the above is that, given
|  ·value space·  A and ·value space·  B where A and B are not
|  related by ·restriction· or ·union·, for every pair of values
|  a from A and b from B, a != b.

I'd like this WG to report our problems with that text.
Failing that, I guess Jeremy and I can report it.

> - types derived by restriction correspond to rdfs:subClassOf
> - don't use xsd:QName, xsd:ENTITY, xsd:ENTITIES

Amen. I came to that same conclusion in my investigation.
http://www.w3.org/2000/10/swap/util/datatypes.n3

I found that all these were goofy:

    # dt:QName # omitted due to ambiguity
    # dt:NOTATION # omitted; DTD support not merited
    # NMTOKEN
    # NMTOKENS
    # ID
    # IDREF
    # IDREFS
    # ENTITY
    # ENTITIES

some for more aesthetic than technical reasons, I suppose.

> - even if we stick to the bits that are clear then implementation looks
> hard.

Yes; I didn't have this information when we made our 11Oct
decision.

http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Oct/0131.html
(items 7 and 8)

Though I was vaguely concerned...

[[
I'm quite concerned that the rdf:datatype proposal
is too complex to deal with in a timely manner;
The sorts of questions Graham asks in his 30Sep
message...
  http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Sep/0370.html
could take quite a while to sort out.

We really expect to
get all this abstract syntax of integers/dates stuff right?
]]
-- http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Oct/0031.html

Likewise the 6Sep decision
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Sep/0081.html
(item 10)

I'm considering asking to reopen them.

> Particularly any test that relies on finiteness of a datatype, or of an
> intersection between datatypes.
> 
> 
> Another hard entailment:
> 
> _:a rdfs:subClassOf xsd:postiveInteger .
> _:a rdfs:subClassOf xsd:byte .
> 
> entails
> 
> _:a rdfs:subClassOf xsd:unsignedLong .
> 
> 
> (I don't think my paper helps much with that one).
> 
> Jeremy
> 
> 
> 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 26 November 2002 10:16:51 EST

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