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Re: ISSUE: Malformed DAML+OIL Restrictions

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 16 May 2002 19:08:38 -0400
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org
Message-Id: <20020516190838I.pfps@research.bell-labs.com>
From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: ISSUE: Malformed DAML+OIL Restrictions
Date: Thu, 16 May 2002 18:01:35 -0400

> At 2:35 PM -0400 5/16/02, Peter F. Patel-Schneider wrote:
> >TITLE:       Malformed DAML+OIL Restrictions
> >DESCRIPTION: DAML+OIL allows for restrictions that are malformed.
> >	     Restrictions with missing components (e.g., a
> >	     restriction with no daml:onProperty triple) have no
> >	     semantic impact, even though treating them as RDF would
> >	     indicate that there should be some semantic import. 
> >	     Restrictions with extra components (e.g., a restriction with
> >	     daml:onProperty triples to more than one property) have
> >	     unusual and misleading semantic impact (in general equating
> >	     the extensions of two or more well-formed restrictions). 
> >
> >	     Both of these should be syntactically illegal in OWL.
> >RAISED BY:   Peter F. Patel-Schneider
> >
> Peter - issues shouldn't include solutions (i.e.  that these should 
> be syntactically illegal in OWL) - maybe "Perhaps both of these 
> should..." would be better wording?


> Also, please explain what you mean by syntactically illegal?  My 
> understanding is that we decided we would use RDF/XML as the exchange 
> language, and triples graphs to convey meaning, so how would you keep 
> these from being syntactically expressible?  Semantically illegal I 
> understand, syntactically I don't understand

Well, one possibility would be to state that not all RDF graphs are
valid OWL ontologies, and give conditions determining which RDF graphs are
valid ontologies.  This would, however, indeed be a solution.  It wouldn't
fit too well with the DAML+OIL way of doing things, but it would fit much
better with the dark triples approach.

>   thanks
>   JH

Received on Thursday, 16 May 2002 19:08:46 UTC

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