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

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