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Re: AtomList infinite or cyclic in all models

From: Ian MacLarty <iml@missioncriticalit.com>
Date: Tue, 20 Feb 2007 15:54:14 +1100
To: Bijan Parsia <bparsia@isr.umd.edu>
Cc: Ian MacLarty <iml@missioncriticalit.com>, Dave Reynolds <der@hplb.hpl.hp.com>, www-rdf-rules@w3.org
Message-ID: <20070220045414.GH3284@cleopatra>

On Mon, Feb 19, 2007 at 11:02:53AM +0000, Bijan Parsia wrote:
> 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.
> 

I have no problem with changing the file, in fact I'm using a modified
version of http://www.daml.org/rules/proposal/swrl.owl for development
work (in my modified version I have simply changed the cardinality
restrictions to maxCardinality restrictions).

I was hoping that by raising the issue on this mailing list I could get
the official proposal changed :-)  Any chance of that, or am I barking
up the wrong tree?

> (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.)
> 

I'm not disagreeing with you, but the fact remains that the SWRL syntax
is defined in an OWL file, and as such it would seem logical to use OWL
tools to automatically generate a SWRL parser, which is exactly what I'm
trying to do.

Ian.
Received on Tuesday, 20 February 2007 04:55:20 UTC

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