W3C home > Mailing lists > Public > public-owl-wg@w3.org > November 2007

Re: Punning and the "properties for classes" use case (from public-owl-dev)

From: Ian Horrocks <Ian.Horrocks@comlab.ox.ac.uk>
Date: Sun, 4 Nov 2007 19:37:29 +0000
Message-Id: <CEC7FAAA-4C5E-4733-B8BF-E507301E1E22@comlab.ox.ac.uk>
Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, Michael Schneider <schneid@fzi.de>, public-owl-wg@w3.org
To: Jeremy Carroll <jjc@hpl.hp.com>

It still isn't clear to me why this is perceived to be a problem,  
much less if/why there is an *actual* problem.

W.r.t. the perception, Alan has explained that punning involves no  
change to the status of uris, just a pragmatically motivated  
weakening of the semantics in the DL case and a consequent loss of  
entailments. I would like to understand better if/why this doesn't  
address the perception issue.

W.r.t. actual problems, I seem to recall someone (Jeremy?) saying  
that they believed that punning would be problematical from the point  
of view of the RDF mapping and/or Full semantics, but I don't recall  
any details being provided. I would also like to know if there is any  
more information on the (non-) existence of such problems.


On 2 Nov 2007, at 16:36, Jeremy Carroll wrote:

> Alan Ruttenberg wrote:
>> Ah well, since I am cited I will reply :)
>> (I guess I should say "chair hat off")
> (while I raise a couple of points that could be viewed as   
> procedural rather than substantive, I prefer you to keep your chair  
> hat off while we have a discussion - as a complete aside, I have  
> found my own preference for hat-wearing to have resulted in a  
> rather negative reception in a variety of places).
>> To summarize, I think that Michael accurately calculates the  
>> entailments, that these are no new surprise, and that they are a  
>> necessary consequence of exactly the articulated trade off. In  
>> summary, I don't see anything new in this analysis.
> I am glad we agree on the facts. I don't believe these issues are  
> stated with as much clarity in the member submission docs, or  
> elsewhere in the WG archive, hence my sense of 'newness'. I don't  
> know how new these issues are to the WG as a whole, but I suspect  
> most participants are not up to speed on all logically consequences  
> (and non-consequences) of the member submission documents.
>> That the current proposal does not satisfy all use cases is not  
>> surprising. The alternative (no alternative provided) provides  
>> fewer. I'd urge that in order to move the conversation forward,  
>> that some concrete alternative proposals be put forward - these  
>> proposals should at least offer increased functionality in the  
>> direction desired, should not require new research, as that would  
>> be outside the mandate of the charter, and provide for sound,  
>> complete, and decidable reasoning, to provide for the user  
>> community that depends on these aspects of OWL DL.
> By default, in a WG trying to provide a relatively small revision  
> on an established specification, the alternative to making a change  
> is to make no change.
> This is HP's preferred option here: i.e. no change from OWL 1.0:  
> punning prohibited in OWL DL (at least in the RDF form); when a uri  
> is used, this takes you into OWL Full, and each URI denotes one thing.
> I point to charter text in favour of this position:
> [[
> For each new feature, if there is doubt or a perceived problem with  
> respect to this issue, the guideline should be to not include the  
> feature
> ]]
> and
> [[
> The existing compatibility between OWL DL and OWL Full should be  
> preserved
> ]]
> both of which seem to me to be directly applicable to punning, and  
> to argue in favour of the HP preference.
> Jeremy
Received on Sunday, 4 November 2007 19:38:08 UTC

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