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RE: SEM Solipsistic answers to Peter's entailments and Paradox

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 18 Mar 2002 10:04:26 -0500
To: michael.smith@eds.com
Cc: jjc@hplb.hpl.hp.com, www-webont-wg@w3.org
Message-Id: <20020318100426H.pfps@research.bell-labs.com>
From: "Smith, Michael K" <michael.smith@eds.com>
Subject: RE: SEM Solipsistic answers to Peter's entailments and Paradox
Date: Mon, 18 Mar 2002 08:47:57 -0600

> Peter,
> 
> When you say
> 
> > However, this is not what happens, because of RDF
> 
> I think what you mean to say is we are in agreement!  If our choice of
> layering forces us to  let RDF impose this sort of interpretation we are in
> trouble.

I agree that there are problems with the way RDF views the world.

> > > owl:oneOf ( <foo> )
> > > owl:oneOf ( <foo> <foo> )
> > > owl:oneOf ( <foo> <foo> <foo> ) ...
> 
> I was reacting to the example, which seemed to be saying that these were all
> entailed by one another.  If owl:oneOf denotes an ordered list, as your
> translation into RDF indicates, then obviously the three cases are not meant
> to have the same meaning.  They are three different lists.  In which case
> there would be no entailment issue.

Well, the syntax has three different forms, and RDF requires that these
have three different lists (or whatever) that exist in interpretations.
Then RDF requires that there be (the possibility of) three different
classes, each of which would have the same extension.

> I have been taking seriously the notion that DAML+OIL is our point of
> departure.  And the daml:oneOf description in
> http://www.daml.org/2001/03/reference.html reads:
> 
>    This enables us to define a class by exhaustively enumerating its 
>    elements. The class defined by the oneOf element contains exactly 
>    the enumerated elements, no more, no less. 
> 
> From which I assumed it was defining a set.  I don't know what it would mean
> for
> a class to include foo as an element twice.

The DAML+OIL model-theoretic semantics also has three different classes,
each of which has the same extension (IC).

> And yes, I was compacting the syntax to agree with Jeremy's.  Given that its
> OWL, its not clear what the syntax should have been.  Daml would say (?)
> 
> <daml:oneOf parseType="daml:collection">
>   <daml:Thing rdf:about="#foo"/>
>   <daml:Thing rdf:about="#foo"/>
>   <daml:Thing rdf:about="#foo"/>
> </oneOf>

Which is only a shorthand macro, expanding to the daml:list form, so there
is no representational difference between this and a written-out daml:list.

> - Mike

peter
Received on Monday, 18 March 2002 10:05:41 GMT

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