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

From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Date: Wed, 23 Apr 2008 19:18:09 +0200 (CEST)
To: Rinke Hoekstra <hoekstra@uva.nl>
Cc: mak@aifb.uni-karlsruhe.de, Michael Schneider <schneid@fzi.de>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, public-owl-wg@w3.org
Message-id: <Pine.LNX.4.64.0804231914440.2230@frege.inf.tu-dresden.de>
On Wed, 23 Apr 2008, Rinke Hoekstra wrote:
>
> On 23 apr 2008, at 18:30, Markus Krötzsch wrote:
>> 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).
>
> Hi Markus,
>
> I guess I agree with you on this point... it would be a shame to have the 
> structural restrictions get in the way of something that *can* be expressed 
> without changing the semantics. Aren't we then just speccing an ill-matched 
> syntax?
>
> How big / numerous do you expect the special cases to be?

To me, this sounds like opening Pandora's box. I guess there are loads
of special cases that one could allow. Where to start and where to
stop?  Moreover, people already find the non-structural restrictions awkward
and difficult to understand. Now we want non-structural restrictions with
(potentially a lot of) exceptions to them? <shiver>.

I like the work of Markus on rules, but I am sceptical to start poking
holes into our non-structural restrictions. Too ad-hoc.

greetings,
 		Carsten

> -Rinke
>
>
>> 
>> 
>> 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
>
> -----------------------------------------------
> Drs. Rinke Hoekstra
>
> Email: hoekstra@uva.nl    Skype:  rinkehoekstra
> Phone: +31-20-5253499     Fax:   +31-20-5253495
> Web:   http://www.leibnizcenter.org/users/rinke
>
> Leibniz Center for Law,          Faculty of Law
> University of Amsterdam,            PO Box 1030
> 1000 BA  Amsterdam,             The Netherlands
> -----------------------------------------------
>
>
>
>

--
*      Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden       *
*     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de     *
Received on Wednesday, 23 April 2008 17:18:46 GMT

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