Re: PROPOSAL to *close* (not postpone) ISSUE-83

On Dec 13, 2007, at 10:47 AM, Jim Hendler wrote:

> WHile I don't actually disagree with Peter on this one, I do think  
> there are several things incumbent on us in these issue
>  1  - we need to document that these features are allowed in Full

This is in question. Can you point to an precedent  from OWL 1.0?  
Whether we *do* document them is open. I don't see evidence that we  
*need* to. My instinct would be to say that user facing documentation  
regarding this would be at the discretion of the contributors to the  
documentation.

>  2 -  close vs. postpone may, in some cases, depend on whether we  
> think in the future their might be a solution -

Exactly. That's why issue-83 will be closed. There is no solution.

> inverseFunctional datatypes, for example, have led to "key"s which  
> we are at least considering for 1.1 - so if in some cases, and this  
> might or might not be one, we think there might be limited  
> solutions that would be decidable, we should consider postponing  
> with a note to that effect.

Right.

>  From the point of view of this WG, close vs. postpone has little  
> difference, but from the pov of a future WG, this shows them there  
> might be interest in the issue if a technical solution can be found

I agree with above. Don't think the next statement is relevant. If  
that happens then they will need to look at the closed issues too.

> or if at some future date a WG decides to stop worrying so much  
> about keeping OWL Full and OWL DL as tightly coupled as they are now.
>  -JH
>
>
>
> On Dec 13, 2007, at 10:05 AM, Peter F. Patel-Schneider wrote:
>
>>
>> Issue-83 asks for property chains on both sides of subproperty  
>> axioms.
>>
>> As pointed out by Uli Sattler
>> http://lists.w3.org/Archives/Public/public-owl-wg/2007Nov/0600.html
>> this makes OWL 1.1 undecidable.
>>
>> Contrary to what Ian Horrocks says
>> http://lists.w3.org/Archives/Public/public-owl-wg/2007Dec/0012.html
>> this feature would automatically be in an OWL
>> Full version because there would have to be in OWL Full a semantic
>> treatment of property chains and then there would be no way of  
>> excluding
>> them from both ends of a rdfs:subPropertyOf axiom.
>>
>> I therefore propose that we CLOSE ISSUE-83 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:  If the "undecidability" was not present above then it would be
>>      reasonable to POSTPONE the issue.  However, undecidability
>>      conflicts with the goals of OWL DL (and OWL 1.1) and thus I
>>      strongly believe that CLOSURE is much more appropriate.
>>
>
> "If we knew what we were doing, it wouldn't be called research,  
> would it?." - Albert Einstein
>
> Prof James Hendler				http://www.cs.rpi.edu/~hendler
> Tetherless World Constellation Chair
> Computer Science Dept
> Rensselaer Polytechnic Institute, Troy NY 12180
>
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