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Re: draft question: option C

From: Dan Connolly <connolly@w3.org>
Date: 16 Oct 2002 20:38:49 -0500
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: Pat Hayes <phayes@ai.uwf.edu>, w3c-rdfcore-wg@w3.org
Message-Id: <1034818730.4220.730.camel@dirk>

On Wed, 2002-10-16 at 14:16, Brian McBride wrote:
> At 10:25 15/10/2002 -0500, pat hayes wrote:
> [...]
> >>I want to be sure that whatever spec we come up with,
> >>I can continue to use the datatype property idiom...
> >>     <k:Thursday r:about="#_thu10">
> >>         <dt:date>2002-10-10</dt:date>
> >>     </k:Thursday>
> >>         -- http://www.w3.org/2002/10dc-uk/itin3.rdf
> >>
> >>So far, our (published WD) specs have been consistent
> >>with a view that classes and properties are disjoint. (In
> >>SWAD, we use that assumption for lint-style checking.)
> >>The 6Sep decision seems to conflict with the
> >>use of the datatype property idioim under
> >>the disjointness-of-properties-and-classes
> >>assumption.
> >
> >I was not aware that there was any such assumption. On the contrary, in 
> >fact: the MT has been designed to allow the possibility of a class and a 
> >property being the same. If this is an assumption, maybe we should reflect 
> >it formally in the language. Certainly that would make the Webont work a 
> >little simpler.
> We discussed this.  It was felt that asking users to distinguish between 
> two uri's for a datatype, one for the class and one for the property would 
> be unnecessarily confusing.

Er... it was also felt that confusing the value space with
the mapping is unnecessarily confusing; I'm not sure if that's
part of the discussion you're talking about, since you
don't give a citation, but it is a matter of record:

" The proposal treats datatypes as if they were the classes which
    conventionally have the same name (eg "integer"), but according to
    the XMLSchema spec, they are not."
-- http://lists.w3.org/Archives/Public/www-rdf-logic/2001Feb/0091.html

> The notion that classes and properties were not disjoint has been around 
> for many months

Which notion, exactly? I see two:

	(a) the RDF specs don't guarantee that
	classes are disjoint from properties

	(b) the RDF specs guarantee that
	classes and properties intersect.

(a) has been around for a while; (b) has been with us only
since 6 Sep.

Even in situation (a), some folks can advocate
"keep your properties separate from your classes"
as a best practice (sorta like ala # vs /) while the spec
remains silent on the issue.

With the WG proposing (b), it forces those
of us who advocate keeping properties and
classes separate to object.

> and has found general acceptance.

I don't think (b) has found general acceptance.
It hasn't found acceptance among the developers
I work with.

>  I'm not convinced that 
> SWAD's lint application is sufficiently strong justification to reopen this.

Well, perhaps it's not worth re-opening the issue at this
point; we're clearly not going to make everybody happy with
any datatypes design.
But I couldn't let your "everybody thinks this is just fine"
go unqualified.

I'm not sure I'm going to be able to get this design thru
last call without objections from the folks I work with.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 16 October 2002 21:38:12 UTC

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