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Re: PRPOSAL to close ISSUE-8

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Thu, 13 Dec 2007 13:31:57 -0500
Message-Id: <318B3213-2535-465B-A574-6C18A986CBB8@gmail.com>
Cc: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, public-owl-wg@w3.org
To: Uli Sattler <sattler@cs.man.ac.uk>


On Dec 13, 2007, at 1:24 PM, Uli Sattler wrote:

> On 13 Dec 2007, at 16:04, Alan Ruttenberg wrote:
>
>> I have had a discussion with Uli about this, and it seems that a  
>> limited form of this would not compromise decidability - e.g. no  
>> binary comparisons other than equality. She said she would write  
>> up a proposal.
>
> ...I seem to remember that i agreed to have a think (!) about it
Yes.
> - and I had: it seems to me that (i) we would need to "fork" OWL11  
> in a difficult to understand way (i.e., you can either use datatype  
> properties at the end of property chains or, say,  comparisons, but  
> not both), and

This doesn't seem in principal different than transitive properties  
and cardinality constraints. Is it? If so, how would you characterize  
the difference?

> (ii) we would need to ask implementors whether they would be  
> willing to implement this.

Yes.

> I would thus favour to not allowing them at all....Carsten?

Yes, but we have two groups which clamor for them - Jim and Jeremy  
representative of them, and they are kind of obviously useful. Could  
we at least have the technical aspects of the case where they are not  
used in comparisons laid out?

Anyways, I think it would be useful to have that in front of us,  so  
we could have something concrete to ask the implementors about.

-Alan

>
> Cheers, Uli
>
>> -Alan
>>
>> On Dec 13, 2007, at 9:56 AM, Peter F. Patel-Schneider wrote:
>>
>>>
>>> Issue-8 asks for property chains that end with data properties.
>>>
>>> Adding this construct to OWL 1.1 would compromise decidability.
>>> This feature would automatically be in an OWL Full version  
>>> because in
>>> OWL Full data properties are also object properties.
>>>
>>> Later discussion asked whether having data properties in the  
>>> middle of
>>> a chain can be done.
>>>
>>> In OWL 1.1 such chains would have an empty extension, and thus be
>>> useless.  The situation in OWL Full is the same as for data  
>>> properties
>>> at the end of a chain.
>>>
>>> I therefore propose that we CLOSE ISSUE-8 (even though it is not  
>>> even
>>> OPEN) without doing anything on the twin grounds that it both
>>> compromises decidability in OWL 1.1 and is not handled by tools, and
>>> that there is nothing special that needs to be done in OWL Full.
>>>
>>> Peter F. Patel-Schneider
>>> Bell Labs Research
>>>
>>> PS: I'm proposing handling ISSUE-8 in this manner as is it is  
>>> closely
>>>     related to ISSUE-83.
>>>
>>
>>
>
Received on Thursday, 13 December 2007 18:32:26 GMT

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