Re: Property chain conflicts with cardinality

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Re: Property chain conflicts with cardinality

Rinke Hoekstra-4
Hi Andrew, Cheng,

Andrew is right. Cardinality constraints are not allowed on properties  
whose semantics depend on 'composite properties', such as property  
chains or transitivity. See the OWL 2 (draft) specification at [1].  
The same holds for functionality/inverse functionality: transitive  
properties and property chains cannot be either.

-Rinke

[1] http://www.w3.org/2007/OWL/wiki/Syntax#Global_Restrictions_on_Axioms

On 29 jul 2008, at 11:38, [hidden email] wrote:

>
> Message: 4
> Date: Tue, 29 Jul 2008 11:01:00 +0200
> From: "Gibson, A.P." <[hidden email]>
> Subject: Re: [p4-feedback] Property chain conflicts with cardinality
> constraints
> To: "Submit feedback for Protege 4.0 alpha"
> <[hidden email]>
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Cheng,
>
> I think that the combination of a cardinality restriction on a  
> property with a role chain makes the inference you expect  
> undecideable. As such I dont think this is a bug, its just one of  
> those things you cant say in OWL.
>
> I'm sure a logician will be able to explain this more cleary (and  
> tell you if I am right!), but I'm pretty sure the overall effect is  
> similar to the undecideablility that comes from putting cardinality  
> constraints on transitive properties. Unlike inconsistencies,  
> undecideable combinations of axioms are not obvious through the  
> interface until you get differences in reasoning output like the one  
> you have here.
>
> You can see the same behaviour yourself if you create a transitive  
> property that links a -> b -> c1 & c2. Without the cardinality  
> constraint you get a --> c1&c2, but when you add one in, like with  
> your initial observation, the inferences disappear.
>
> I seem to remember that I accidentally did this once, and it was  
> picked up through the OWL species checker of Pellet, which was  
> telling us that it was OWL-Full because of the combination of  
> axioms. I dont know if the species checker is supported for OWL2 but  
> it would be worth finding out.
>
> Thanks for building the test model, and I hope this helps.
>
> Dr Andrew Gibson
> Universiteit van Amsterdam
>
> -----Original Message-----
> From: [hidden email] on behalf of Lu, Cheng
> Sent: Tue 7/29/2008 8:02 AM
> To: [hidden email]
> Subject: [p4-feedback] Property chain conflicts with cardinality  
> constraints
>
> Hi, I have the following problem when testing the property chain  
> feature.
>
> Classes: A, B, C
> Object Properties: hasB, hasC
> hasB - Domain: A   Range: B
> hasC - Domain: A, B   Range: C
>
> Property chain: hasB o hasC ->hasC
>
> Individual: a, b, c1, c2 (a: A, b: B c1, c2: C)
> Statement:
>    a. hasC(c1)
>    a. hasB(b)
> b. hasC(c2)
>
> At this point, as expected, there is an inferred statement by  
> property composition in
> the knowledgebase:
> a. hasC(c2)
>
> The problem occurs when any cardinality constraint is defined on A's  
> hasC property (e.g.
> A. hasC max 3 C; A. hasC exact 2 C; etc.); the inferred statement  
> a.hasC(c2) disappears
> form knowledgebase and Pellet query results.
>
> We are using prot?g? 4.0 alpha to create the ontology and tested  
> this bug in both
> integrated Pellet 1.5 in prot?g? and external Pellet 1.51.
>
>
> Regards
> _______________________________________________
> p4-feedback mailing list
> [hidden email]
> https://mailman.stanford.edu/mailman/listinfo/p4-feedback
>
>

-----------------------------------------------
Drs. Rinke Hoekstra

Email: [hidden email]    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
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