Re: closing ISSUE-22 (special syntax for role rule)

I agree, but I think it is not quite so simple. The main issue here might be 
that, while many rules can be expressed in OWL2, some of these encodings 
would violate the structural restrictions without need. I suggest we consider 
at least some special cases of rules here to waive that restriction, and make 
room for future rule interfaces on top of OWL2. I agree that we should not 
make a new rule language (if anything, one would take OWL2 rules to RIF, I 
guess).

For people interested in a formal spec of a larger class of "OWL2 rules", I 
point to the following works of ours on the topic:

http://korrekt.org/page/SROIQ_rules
http://korrekt.org/page/ELP

The main work here is to show that one can use rules (hence many other OWL 2 
features) with our tractable profiles without hurting the polynomial 
reasoning. Moreover, there is also the Protege plugin by Francis Gasse (see 
OWLED-Washington papers, joint work with Volker Haarslev and Uli Sattler) to 
actually work with such rules -- maybe more concrete proposals could also 
emerge from that experience?

Regards,

Markus

On Freitag, 18. April 2008, Michael Schneider wrote:
> Hi!
>
> This has been an interesting exercise for me at that time, and helped me to
> better understand the power of sub property chains. It is nice to see that
> something like this can actually be expressed within OWL 2 DL. But directly
> supporting this as a feature in the OWL language itself would look rather
> strange to me.
>
> So I concur: +1 for REJECTING this issue.
>
> Cheers,
> Michael
>
> >-----Original Message-----
> >From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org]
> >On Behalf Of Peter F. Patel-Schneider
> >Sent: Friday, April 18, 2008 1:43 PM
> >To: public-owl-wg@w3.org
> >Subject: closing ISSUE-22 (special syntax for role rule)
> >
> >
> >On 16 January 2008 Bijan added a note to the proposal for ISSUE-22:
> >
> >  I think we should close this with no action. Here's why:
> >
> >  1) It's a new feature and there is no concrete proposal and I spent a
> >  few minutes trying to think of a syntax and had no good one other than
> >  the rule itself
> >
> >  2) Having just this one rule (which wouldn't be DL safe!) is very
> >  strange and might conflict with rule extensions
> >
> >  3) It seems that the best place for this is in a "Decidable swrl
> >  compiler" (as a visitor here was working on). There are *lots* of
> >  rules that you can compile using the new expressive property
> >  axioms. Why *this* one? Just because we thought of it? Better to
> >  encourage the development of these SWRL compilers and leave it to a
> >  "decidable fragments of SWRL" group.
> >
> >  [Bijan Parsia]
> >
> >There does not appear to have been any futher discussion.
> >
> >I agree with Bijan's comments, and propose that ISSUE-22 be closed in
> >this fashion.
> >
> >Peter F. Patel-Schneider
> >Bell Labs Research



-- 
Markus Krötzsch
Institut AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe
phone +49 (0)721 608 7362          fax +49 (0)721 608 5998
mak@aifb.uni-karlsruhe.de          www  http://korrekt.org