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Re: stating that something doesn't exist

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 22 May 2008 07:52:28 +0100
Message-Id: <72E44CA6-DF1C-45D6-B06C-D081A28E3C79@cs.man.ac.uk>
Cc: <semantic-web@w3.org>
To: "Johnson, Matthew C. (LNG-HBE)" <Matthew.C.Johnson@lexisnexis.com>

On May 21, 2008, at 10:10 PM, Johnson, Matthew C. (LNG-HBE) wrote:

> Hi,
>
> I’m slowing soaking in what OWL can and cannot do and after reading  
> the “Lessons For Ontology Writers” post [1] by Ian Davis, I thought  
> I’d go ahead and ask this capabilities question here.
>
> In OWL, can you directly define a property that says that something  
> does not occur.  My current use-case is in determining hyper- 
> linking relationships between various publications.  The following:
[snip]
> Lets me say that pub 1 links to pub 2 and that pub 3 links to pub  
> 2.  However, if I understand the open-world assumption, I cannot  
> assume that pub 2 does not link to pub 3.  I would need to define  
> something like:
>
> mysch:notLinksTo a rdf:Property .
>
> to explicitly state this fact that pub 2 does not link to pub 3.
>
> My question is whether it is possible in OWL to define a property  
> whose range of acceptable instances is the list of instances that  
> do not exist as an object in a mysch:linksTo statement (for a given  
> publication)?

Do you really mean *for a given* publication, or *for any*  
publication? The latter is easy, define the range of your property to  
be those individuals that complementOf(someValuesFrom(inverseOf 
(linksTo), owl:Thing)).

If you need it for a specific individual replace the someValuesFrom  
with a hasValue and the owl:Thing with that individual. If you want  
it to be a class of pubs, replace owl:Thing with that class.

Cheers,
Bijan.
Received on Thursday, 22 May 2008 06:53:23 GMT

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