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Re: Intersection of properties?

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Sun, 3 Aug 2008 21:42:02 +0100
Message-Id: <E7A50E34-9A1A-4E67-8F4F-773B1CF8D157@cs.man.ac.uk>
Cc: Michael Schneider <schneid@fzi.de>, Owl Dev <public-owl-dev@w3.org>, Uli Sattler <sattler@cs.man.ac.uk>, Markus Krotzsch <mak@aifb.uni-karlsruhe.de>
To: Jeff Thompson <jeff@thefirst.org>

On Aug 3, 2008, at 8:57 PM, Jeff Thompson wrote:

> Bijan Parsia wrote:
>> On Aug 3, 2008, at 7:58 PM, Jeff Thompson wrote:
>> [snip]
>>> I sounds like many implementors
>> No, it doesn't sound like that. Those were all theory papers.
>>> see that even OWL 2 is not expressive
>>> enough to solve their data processing needs, and so everyone has
>>> their own extensions in Pellet, etc.
>> ? No. The implementation of ALBO is not, by any means, production  
>> quality (or would purport to be even vaguely scalable to realistic  
>> kbs). There's only one, sorta implementation of PDL (Peter's DLP,  
>> which is sorta defunct).
>> So, I don't know where you're getting this from :)
>>> And yet, the argument against
>>> adding more expressiveness to OWL 2 (still decidable) is the fear
>>> that not enough people will implement it and so that "OWL 2  
>>> compliant"
>>> won't mean much.
>> What? The argument against boolean role boxes, in general, is that  
>> it's relatively hard to do and there's been relatively little  
>> demand for it. ALBO is *very* expressive but, you know, doesn't  
>> have cardinality restrictions.
>> I personally don't feel a burning desire for role conjunction.  
>> Perhaps you could list use cases?
>
> I already implemented SWRL in Browlser.
> http://browlser.sourceforge.net/

Actually, you haven't (at least I'm very skeptical that you have). At  
least not how it is properly understood. See:
	http://clarkparsia.com/weblog/category/semweb/rules/swrl/

You may have implemented some sort of DL Safe variant.

> And so I'm trying to understand which of the implicit rules
> in the OWL 2 axioms can be used instead of SWRL rules.

There is some good recent work on this. Which I'm having trouble  
finding at the moment ;) I ping Uli and Markus for the pointers.

> The "uncle" rule with role chains is a good example of where OWL 2 on
> its own is good enough without having to spell out the rule in SWRL.
> There are many SWRL rules I use which are of the form of role  
> conjunction.

If you are happy with the DL Safe version (as I suspect you are),  
then there are several implementations and you can have all these.

> I also use the equivalent of role chains that end in a datatype but  
> the
> OWL working group has already rejected these.
> http://www.w3.org/2007/OWL/tracker/issues/8

Sufficient feedback could change things. It's hard to act with out data.

> So I'm trying to understand what's "in" and what's "out" and why.

For the role chains and datatype, this is key:
	http://lists.w3.org/Archives/Public/public-owl-wg/2007Dec/0174.html

Sensible implementation of path based concrete domains is a open  
challenge. DL Safe rules with data properties have some challenges  
but are much more likely to be robustly implemented in the near term  
(say, year).

>>> I know it's a difficult political task to balance.
>>> Is the general assumption that there will need to be several more
>>> revision cycles to OWL before a large number of people will use it
>>> as specified without needing to add their own incompatible  
>>> extensions?
>> I think you're confused. OWL already is used by a large number of  
>> people without needing to add their own incompatible extensions.  
>> If you have a strong need for very expressive role boxes, I  
>> suggest you submit a paper to OWLED detailing your needs.
>
> Thanks for the quick feedback.  There's a lot of work going on  
> which is
> exciting.

Yep. Please make your needs known!

Cheers,
Bijan.
Received on Sunday, 3 August 2008 20:42:46 GMT

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