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Re: A proposal for clarifying the definitions of datatype maps, take II

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 30 Jul 2009 04:45:38 -0400
Message-ID: <20090730.044538.89006430.pfps@research.bell-labs.com>
To: <alanruttenberg@gmail.com>
CC: <ian.horrocks@comlab.ox.ac.uk>, <hendler@cs.rpi.edu>, <boris.motik@comlab.ox.ac.uk>, <public-owl-wg@w3.org>
I am confused.

It appears to me that http://www.w3.org/2007/OWL/wiki/Syntax now
precisely defines OWL 2 DL and that
http://www.w3.org/2007/OWL/wiki/Conformance simply states that
conformant OWL 2 DL tools must correctly handle OWL 2 DL.

What more needs to be said?

peter

PS:  Of course, what may be needed is a statement (somewhere) saying
how the situation previously was messed up and describing how this was
fixed, perhaps something like:

	[Previously, SS&FS did not completely specify which datatypes
	were part of OWL 2 DL.  The requirement that conformant OWL 2 DL
	tools implement all datatypes in the OWL 2 DL datatype map was
	stated in Conformance.  Now SS&FS completely defines OWL 2 DL
	ontologies and Conformance simply defers to the definitions in
	SS&FS.] 

PPS: Perhaps the confusion is to what MUST be in OWL 2 DL.  Maybe Boris
needs to go through SS&FS and add MUST in every definition, as in "Any
SubDataPropertyAxiom MUST be a DataPropertyAxiom" instead of deferring
to the BNF definition of DataPropertyAxiom.



From: Alan Ruttenberg <alanruttenberg@gmail.com>
Subject: Re: A proposal for clarifying the definitions of datatype maps, take II
Date: Wed, 29 Jul 2009 20:44:57 -0500

> On Wed, Jul 29, 2009 at 6:30 PM, Ian
> Horrocks<ian.horrocks@comlab.ox.ac.uk> wrote:
>> Alan,
>>
>> Getting rid of this MUST in Conformance is one of the main purposes of the
>> cleanup -- the MUST was an ugly sticking plaster that was needed only in
>> order to cover up the fact that Syntax didn't sufficiently constrain the OWL
>> 2 Datatype map. Syntax now does this. As a result, we no longer need the
>> sticking plaster.
> 
> There were three aspects of how the constraints needed to be made
> clear. First, it needed to be tightened so that it was clear that
> additional datatypes beyond a certain set pushed it out pushed it out
> of DL. Second it needed to be clarified that a minimum set of
> datatypes needed to be supported by OWL DL tools, and third it needed
> to be made clear that we base our definitions on the established
> external specifications such as XML Schema.
> 
> I believe the changes best served the first and third, but make it
> hard to determine the second, which is why the removal of the MUST,
> which directly spoke to the second, caught my attention. I see no harm
> whatsoever in making the statement in conformance, so I don't
> understand what the objection is. People will look to conformance to
> understand issues like this.
> 
>>
>> Conformance now simply says that conformant systems have to support the
>> language as defined in the spec -- which is clearly what it always should
>> have said. Of course some analysis is required in order to understand the
>> spec, but this is true for all parts of it and not just datatypes.
> 
> Yes, but we don't have to make it harder for them. I agree that we
> should not make a habit of having verbatim repeat elements in one
> document and another. However, this is not the case on this issue - we
> are simply clarifying something that might otherwise need a rather
> careful read to get otherwise, in the place where one expects to find
> such clarifications. (Actually we would be not removing a
> clarification).
> 
> The proposal Boris made was to clarify/move things around. Your
> summary: "What I understand is that you are just suggesting moving
> things around to make docs more consistent". The MUST was not moved
> from conformance to Syntax. Rather it was removed and a need to make
> an inference was left in its place (i.e. it is less clear). Still, on
> reading, I find it difficult to construct an argument that tools MUST
> support all the datatypes, given what is in syntax now. So I don't see
> the changes as completely meeting the proposal, despite me agreeing
> that otherwise they improve things.
> 
> -Alan
> 
> p-Alan
> Best,
> Alan
Received on Thursday, 30 July 2009 08:56:27 GMT

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