Re: Covering Axiom Question

Hi Kevin

If I understand correctly, this does not alter the semantics of the covering
> axiom that can be implemented today using disjoint classes which in union
> comprise the equivalent class or super class of the covered class.
>

Not sure I catch exactly what you mean here, but my hunch is the answer is
"no". OWL 2 provides just a shortcut to avoid the declaration of n˛ pairs of
disjoint classes (unless I miss something)


> What I don't understand is why an instance of the covered class does not
> create an inconsistency.
> Is this an artifact of the tools, in my case pellet and Protege 4, or is an
> instance of a covered class which is not also an instance of a covering
> class consistent?
>

That's something rather counter-intuitive. but there is no inconsistency in
declaring x to be a direct instance of A when A is the union of B and C
(disjoint or not). In this case, the ontology says that x is either in B or
C (and not in both if the union is disjoint), but the triples at hand do not
allow to conclude in which. The fact that x is an instance of A can even in
some cases be entailed, not declared. Suppose you have defined a property p
of which domain is A, if x p y then x is an instance of A. Of which you
entail that x is either in B or C.

No more no less.

Bernard




> TIA,
> Kevin
>
> On Thu, Oct 1, 2009 at 3:46 AM, Bernard Vatant <bernard.vatant@mondeca.com
> > wrote:
>
>> Kevin
>>
>> I would say DisjointUnion in OWL 2 is exactly what you are looking for
>> http://www.w3.org/TR/2009/PR-owl2-new-features-20090922/#F1:_DisjointUnion
>>
>> Best
>>
>> Bernard
>>
>> 2009/9/30 Kevin Tyson <kevin.tyson@gmail.com>
>>
>>> Greetings,Is it possible to create a covering axiom such that any
>>> instances of the covered class must be a direct instance of one of the
>>> covering classes?Such a structure would be analogous to the "abstract
>>> super class" pattern popular in some O-O programming and modeling languages.
>>> TIA,
>>> Kevin
>>>
>>> --
>>> Kevin P. Tyson
>>> Kevin.Tyson@gmail.com
>>>
>>
>>
>>
>> --
>> Bernard Vatant
>> Senior Consultant
>> Vocabulary & Data Engineering
>> Tel:       +33 (0) 971 488 459
>> Mail:     bernard.vatant@mondeca.com
>> ----------------------------------------------------
>> Mondeca
>> 3, cité Nollez 75018 Paris France
>> Web:    http://www.mondeca.com
>> Blog:    http://mondeca.wordpress.com
>> ----------------------------------------------------
>>
>
>
>
> --
> Kevin P. Tyson
> Kevin.Tyson@gmail.com
>



-- 
Bernard Vatant
Senior Consultant
Vocabulary & Data Engineering
Tel:       +33 (0) 971 488 459
Mail:     bernard.vatant@mondeca.com
----------------------------------------------------
Mondeca
3, cité Nollez 75018 Paris France
Web:    http://www.mondeca.com
Blog:    http://mondeca.wordpress.com
----------------------------------------------------

Received on Friday, 2 October 2009 08:13:29 UTC