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Re: Nonstructural restrictions

From: Rinke Hoekstra <hoekstra@uva.nl>
Date: Fri, 28 Mar 2008 09:17:01 +0100
Cc: Alan Ruttenberg <alanruttenberg@gmail.com>, colombet@elet.polimi.it, "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
Message-Id: <E46418FB-32DA-4365-906F-531FE385E2AB@uva.nl>
To: Uli Sattler <sattler@cs.man.ac.uk>

Hi Uli,

Hm. Your answer got me a bit confused.. Like Marco, I thought  
ObjectExistsSelf was not allowed on composed properties at all. Are  
you saying they *are* allowed on any class, or just owl:Thing?

If so, I guess the description in the syntax document could use some  
clarification.

-Rinke


On 27 mrt 2008, at 20:24, Uli Sattler wrote:
>
> 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
>>>
>>>
>>
>

-----------------------------------------------
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
-----------------------------------------------
Received on Friday, 28 March 2008 08:17:42 GMT

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