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Re: Allowed types of punning (ISSUE-114)

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Wed, 9 Jul 2008 19:52:17 +0100
Message-Id: <AC8D08C5-4F29-4446-B97E-00494A01C242@cs.man.ac.uk>
Cc: "'OWL Working Group WG'" <public-owl-wg@w3.org>
To: "Boris Motik" <boris.motik@comlab.ox.ac.uk>

On 9 Jul 2008, at 19:23, Boris Motik wrote:
[snip]
> I believe that the use cases for "individual vs. anything" type of  
> punning have been well documented in a number of publications.
> Thus, the only type of punning that could potentially be  
> controversial is "class or datatype vs. some type of property".
>
> Right, I don't expect people really wanting to have a property  
> called "xsd:integer";

Of course, what's more likely is that someone wants to pun a named  
user defined datatype and something else.

> however, I don't see how disallowing it makes
> the spec better. People can do this in OWL Full, and allowing this  
> in OWL DL merely allows us to handle a larger percentage of RDF
> graphs. Moreover, I believe that there is no distinction between  
> the semantics of punning in OWL Full and OWL DL; to be more
> precise, I don't think you can notice the difference at the level  
> of consequences.

Furthermore, there are alignment and refactoring situations where  
this extra syntactic freedom is convenient. (I made this same  
argument for object/data punning). It seems quite odd to think that  
one will never get a class and a datatype or a class and property  
with the same name. One could be migrating legacy data. One might  
have a generative naming scheme. Given that it's easy to  
syntactically detect anyway, it's easy to write lint tools to detect  
it if you think it's bad practice. I don't see how it helps use to  
have catastrophic failure of these graphs.

> The same holds for punning of the form "class vs. some type of  
> property".

Indeed.

I'd like to raise a question about burden of proof. It's unclear to  
me why the burden of proof here lies with the retainers rather than  
the removers (indeed, this was really my point in the telecon). In  
order to remove this feature, we need some consensus or, failing  
that, a vote. It seems to me that there's pretty strong and broad  
opposition to removing this feature (be we've not taken a straw poll)  
and I've not heard a compelling story about why we should remove it.

If I had to appeal to a general principle, it would be Postel's law.

I appreciate that people need to become comfortable with an issue  
(look at me and floats), but we, qua group, need to make progress as  
well. Is it better to go through a lot of debate and *then* be hung?

Cheers,
Bijan.
Received on Wednesday, 9 July 2008 18:50:04 GMT

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