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Re: Imports issue

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Thu, 20 Feb 2003 13:12:48 +0000
Message-ID: <15956.54352.829239.277487@merlin.horrocks.net>
To: Dan Connolly <connolly@w3.org>
Cc: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, Guus Schreiber <schreiber@swi.psy.uva.nl>, www-webont-wg@w3.org

On February 19, Dan Connolly writes:
> 
> On Wed, 2003-02-19 at 18:40, Peter F. Patel-Schneider wrote:
> > From: Guus Schreiber <schreiber@swi.psy.uva.nl>
> > Subject: IImports issue
> > Date: Thu, 20 Feb 2003 00:26:57 +0100
> > 
> > > I'm feeling increasingly uncomfortable about our "imports" resolution 
> > > (see the discussion threads cited in the agenda).
> > > 
> > > Unless we get in the very near future clear evidence this is an 
> > > implementable language feature, I will have to reopen this issue and 
> > > propose to give imports the same informnal status as the versioning stuff.
> > 
> > Huh?  
> > 
> > To implement imports, it suffices to modify an RDF/XML processor as
> > follows:
> > 
> >    Whenever an imports triple is found, first check to the if the object of
> >    the triple has been imported already.   If not, get the document that is
> >    pointed to by the object of the triple and run it through the RDF/XML
> >    processor.  Then merge the result with the current graph.  Only a very
> >    small amount of care is required to prevent loops.
> > 
> > What could be easier?
> 
> Then why aren't tools that do that widely deployed?
> Or at least available to this WG in some form?
> 
> I suggest: because there isn't really a need
> for owl:imports as specified. There are lots
> of ways of meeting the relevant requirements,
> and there isn't community consensus about
> which way is best, or even pretty good.

Hopefully Jeremy and Sean have already satisfied any worries about
implementability.

As far as requirements are concerned, some form of imports mechanism
will certainly be required for any large scale ontology engineering
application (the imports mechanism we now have is probably the bare
minimum).  If we don't include it in the language, then there will
necessarily be bespoke implementations within different tools, which
will seriously damage tool interoperability, which will in turn
seriously impede uptake of the language. Lack of such interoperability
has already been identified as one of the main barriers to the use of
DAML+OIL. (Note that the same applies to comments.)

As far as implementation in general is concerned, as I have mentioned
before, you can't expect implementors to put too much effort in while
the language specification still appears to be unstable!

Ian
Received on Thursday, 20 February 2003 08:13:57 GMT

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