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Re: less-restrictive range and domain terms

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 04 May 2004 16:30:16 -0400 (EDT)
Message-Id: <20040504.163016.08623669.pfps@research.bell-labs.com>
To: pdawes@users.sourceforge.net
Cc: b.fallenstein@gmx.de, www-rdf-interest@w3.org

From: "Phil Dawes" <pdawes@users.sourceforge.net>
Subject: Re: less-restrictive range and domain terms
Date: Tue, 4 May 2004 19:47:33 +0100

> Hi Benja, Hi Peter,
> 
> Benja Fallenstein writes:
>  > -----BEGIN PGP SIGNED MESSAGE-----
>  > Hash: SHA1
>  > 
>  > Peter F. Patel-Schneider wrote:
>  > |>I've recently found myself wanting a less-restrictive version of
>  > |>rdfs:range (or owl:allValuesFrom) and rdfs:domain. I want to say
>  > |>'property *can* have range of class foo' rather than 'property *must*
>  > |>have range of class foo'.
>  > |
>  > | Hmm.
>  > |
>  > | First of all, there is no 'property *must* have range of class foo' in RDF
>  > | or OWL.  All there is is ``property *has* range class foo''.
>  > |
>  > | Second, what do you mean by 'property *may* have range of class foo'?
>  > 
>  > "There exist triples with property P and an object of class foo," rather
>  > than "All triples with property P have objects of class foo," is a
>  > useful interpretation, I presume.
>  > 
> 
> Yep - that's what I meant. Sorry for not being clear.
> 
> Cheers,
> 
> Phil

But suppose that there just doesn't happen to be such a relationship in the
current world.  What happens then?

This is not such a problem for property ranges (but does cause problems
even here), but what about an OWL construct like 
     the class foo may have range bar for property p
Does this mean that foo has to be non-empty?

peter
Received on Tuesday, 4 May 2004 16:32:27 GMT

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