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Re: Intersection of properties?

From: Jeff Thompson <jeff@thefirst.org>
Date: Sun, 03 Aug 2008 11:58:57 -0700
Message-ID: <4895FFF1.3020406@thefirst.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>
CC: Michael Schneider <schneid@fzi.de>, public-owl-dev@w3.org

Bijan Parsia wrote:
> 
> On Aug 3, 2008, at 2:19 AM, Jeff Thompson wrote:
> 
>> Michael Schneider wrote:
>>> Bijan Parsia answered to Jeff Thompson:
>>>>> Consider the rule that if X desires Y and X can_do Y, then X does Y.
>>>>> In Prolog, this would be:
>>>>>
>>>>> does(X, Y) :- desires(X, Y), can_do(X, Y).
>>>>>
>>>>> This is really defining 'does' as the intersection of the
>>>>> properties 'desires' and 'can_do'.
>>>>> I couldn't find something like this in the OWL use cases.  Is there
>>>>> a way to do this in OWL2?
>>   Consider the simpler example "if Y is Desirable and Y is Doable
>> then Y is Done".   In OWL 2 with class intersections:
>> SubClassOf(ObjectIntersectionOf(Desirable Doable) Done)
>> Thus if
>> ClassAssertion(action Desirable)
>> ClassAssertion(action Doable)
>> we can conclude
>> ClassAssertion(action Done)
>>
>> In Prolog:
>> 'Done'(Y) :- 'Desirable'(Y), 'Doable'(Y).
>>
>> I am asking about the same thing with properties.
> 
> Yeah, doubtful and not obvious.  You can add boolean operators on roles 
> in a lot of cases but it generally makes things harder. See:
>     http://www.cs.man.ac.uk/~ezolin/dl/
> and
>     http://iswc2007.semanticweb.org/papers/435.pdf
> 
> (You might also look at ALC_{reg} and PDL.)
> 
> If you are willing for this not to (directly) affect subsumptions, then 
> DL Safe rules will do the job.

I sounds like many implementors 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.  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.  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?
Received on Sunday, 3 August 2008 18:59:41 GMT

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