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Re: AtomList infinite or cyclic in all models

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Mon, 19 Feb 2007 11:02:53 +0000
Message-Id: <315877AF-9DFF-4540-8297-188F54D1A592@isr.umd.edu>
Cc: Dave Reynolds <der@hplb.hpl.hp.com>, www-rdf-rules@w3.org
To: Ian MacLarty <iml@missioncriticalit.com>

On Feb 19, 2007, at 6:33 AM, Ian MacLarty wrote:
[snip]
> This is problematic, because it means that rdf:nil is in the class  
> Atom,
> because of the allValuesFrom restriction on rdf:first for AtomList.
> The SWRL spec doesn't say what the meaning of the rdf:nil atom is
> (the meaning of the rdf:nil AtomList is clear, but not the meaning  
> of the
> rdf:nil Atom).
>
> More generally this is a bad way to define lists, since for any class
> you define a list of in this way, you end up adding rdf:nil to the
> class.  This means you couldn't define lists for two disjoint classes
> using this approach, since then both classes would contain rdf:nil and
> violate the disjointWith constraint.

You could always add an atomNil for the car, but yeah, sorta sucks.  
You could make the value of the allValues Atom or {nil}. But then you  
are back to changing the file.

(Just for the record, I still think it's pointless to get hung up on  
this bit. :) That is an OWL file describing SWRL syntax is an  
inherently silly thing.)

Cheers,
Bijan.
Received on Monday, 19 February 2007 11:03:04 UTC

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