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Re: Can an object property be both functional and transitive?

From: Bijan Parsia <bparsia@cs.manchester.ac.uk>
Date: Mon, 26 Jan 2009 20:41:49 +0000
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, W3C OWL Working Group <public-owl-wg@w3.org>
Message-Id: <D084253D-C226-4207-8C4B-0E78A75ADE4F@cs.manchester.ac.uk>
To: Jie Bao <baojie@gmail.com>

On 26 Jan 2009, at 20:17, Jie Bao wrote:

> Thanks Bijan for the reference

You're welcome.

> On Mon, Jan 26, 2009 at 2:50 PM, Bijan Parsia <bparsia@cs.man.ac.uk>  
> wrote:
>>
>> On 26 Jan 2009, at 19:36, Jie Bao wrote:
[snip]
> It looks the same as the OWL 1 case.

It should be.

> However, we need to be careful
> with the definition of ObjectPropertyAxiom after Figure 15 :
>
> ObjectPropertyAxiom :=
>    SubObjectPropertyOf | EquivalentObjectProperties |
>    DisjointObjectProperties | InverseObjectProperties |
>    ObjectPropertyDomain | ObjectPropertyRange |
>    FunctionalObjectProperty | InverseFunctionalObjectProperty |
>    ReflexiveObjectProperty | IrreflexiveObjectProperty |
>    SymmetricObjectProperty | AsymmetricObjectProperty |
>    TransitiveObjectProperty
>
> It very likely to give users a wrong impression that
> FunctionalObjectProperty axiom and TransitiveObjectProperty axiom (as
> well as for some other simple, non-simple cases) can co-exist for the
> same property. A note to "Global Restrictions on Axioms" may be needed
> here to draw users' attention.

Or we could be more explicit about this in the intro.
[snip]
> Another issue is that, if the UML diagrams are meant to be a normative
> definition of OWL 2,

UML diagrams + the global restrictoins and some other constraints.

> can the "Global Restrictions on Axioms" be part
> of the UML definition,

I don't think so.

> or they are out of the expressivity of UML,
> thus no standard UML tool can actually accept a complete OWL 2
> specification?

I'd be surprised if all the constraints could be expressed in UML.  
Compare with XML Schema --- it's definitely the case that not all the  
constraints can be expressed in XML Schema, not just for OWL, but for  
most languages (e.g., WSDL).

[snip]
>> That condition is even more complex, I'm not sure it's a good idea to
>> add it at this time. (Simple vs.  non-simple is much easier.) I do  
>> hope
>> implementations will go beyond the coarser restriction over time.
>>
> How implementor can be aware of this?

By being familiar with the literature. It's highly likely that more  
liberalizations will be discovered. We can't expect the spec to track  
that.

Cheers,
Bijan.
Received on Monday, 26 January 2009 20:42:31 GMT

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