Re: Nonstructural restrictions

On 27 Mar 2008, at 18:27, Alan Ruttenberg wrote:

>
>
> Begin forwarded message:
>
>> Resent-From: public-owl-dev@w3.org
>> From: "Marco Colombetti" <colombet@elet.polimi.it>
>> Date: March 26, 2008 12:11:47 PM EDT
>> To: <public-owl-dev@w3.org>
>> Subject: Nonstructural restrictions
>> Archived-At: <http://www.w3.org/mid/002e01c88f5c$18ecbb70$7c46fea9@lapcolombetti 
>> >
>>
>> Hi.
>>
>> In http://www.webont.org/owl/1.1/owl_specification.html  “OWL 1.1  
>> Web Ontology Language - Structural Specification and Functional- 
>> Style Syntax - Editor's Draft of 23 May 2007”.
>>
>> in Section 7 “Nonstructural Restrictions on Axioms”,
>>
>> I find that:
>> Only simple object properties are allowed to occur in Ax in
>> ObjectMinCardinality, ObjectMaxCardinality, ObjectExactCardinality,  
>> and ObjectExistsSelf classes, and
>> ObjectPropertyFunctional,  
>> InverseFunctionalObjectProperty,ObjectPropertyIrreflexive,  
>> ObjectPropertyAsymetric, andDisjointObjectProperty axioms.
>> I wonder whether composite properties should also be forbidden in  
>> ObjectPropertyReflexiveaxioms, given that these are equivalent  
>> toSubObjectPropertyOf(owl:Thing,ObjectExistsSelf(P)).
>>

good question:  ObjectPropertyReflexive(P) for a non-simple/composite  
property is ok. This might be a bit hard to see, but i will try to  
explain. It is equivalent, as you say, to

SubClassOf(owl:thing, ObjectExistsSelf(P)),

but this is also ok: in principal, what is difficult for a composite  
property, is

SubClassOf(AClass, ObjectAllValuesFrom(P AnotherClass)),

Ie, universal/all restrictions are difficult for them, but not  
existential/some restrictions as in "ObjectExistSelf"....

  Cheers, Uli


>> Regards,
>>
>> Marco Colombetti
>>
>>
>