W3C home > Mailing lists > Public > www-rdf-rules@w3.org > February 2007

Re: AtomList infinite or cyclic in all models

From: Ian MacLarty <iml@missioncriticalit.com>
Date: Tue, 20 Feb 2007 14:06:51 +1100
To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
Cc: Bijan Parsia <bparsia@isr.umd.edu>, drew.mcdermott@yale.edu, www-rdf-rules@w3.org
Message-ID: <20070220030651.GB3284@cleopatra>

On Mon, Feb 19, 2007 at 12:10:14PM +0000, Henry S. Thompson wrote:
> 
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> Bijan Parsia writes:
> 
> > Are these anomalies? I'm not so sure. It makes nil a bit more like
> > the empty set. One might find that anomalous on some readings of
> > lists, but not on others.
> 
> Fools rush in. . .  I'm curious as to what you are appealing to for
> your judgements about 'real' lists.  I've struggled with this a fair
> bit myself in the context of trying to build a satisfactory ontology
> for XML itself.  I ended up concluding that
> 
>  a) Lists were sequences (*);
>  b) A sequence is best understood as a function from the integers
>     [1..|sequence|] to its members.
> 
> So I'd say that what's been discussed so far in this thread should be
> called OFLispList or some such, since as already remarked it's
> modelling lists using cons-pairs that's causing all the trouble.

I don't think it's using cons pairs that's the problem, the problem is
that *only* cons pairs are used (even the nil list is a cons
pair).

> Then
> some further work is required to axiomatise a useful definition of
> List and/or Sequence.  AtomList is also misleading as a name in that
> there's no constraint that its members be atoms, AFAIK!
> 

The allValuesFrom(Atom) restriction on rdf:first ensures that all
elements of AtomList are Atoms.

Ian.
Received on Tuesday, 20 February 2007 03:08:00 UTC

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