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Re: LANG: syntactic version for imports (and other things)

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 16 Sep 2002 19:23:06 -0400 (EDT)
Message-Id: <20020916.192306.65674644.pfps@research.bell-labs.com>
To: heflin@cse.lehigh.edu
Cc: www-webont-wg@w3.org

From: Jeff Heflin <heflin@cse.lehigh.edu>
Subject: Re: LANG: syntactic version for imports (and other things)
Date: Mon, 16 Sep 2002 17:59:02 -0400

> "Peter F. Patel-Schneider" wrote:
> > 
> > From: Jeff Heflin <heflin@cse.lehigh.edu>
> > Subject: Re: LANG: syntactic version for imports (and other things)
> > Date: Mon, 16 Sep 2002 10:06:27 -0400

[...]

> > > Also, I expected to see some account of the meaning of this construct.
> > > You didn't like my entailment-based version, what would you suggest
> > > instead?
> > 
> > The meaning is the obvious one.  The contents of the imported ontology
> > are considered to be part of the meaning of this ontology.
> 
> I have to admit I am a bit suprised at this answer, especially since it
> is coming from someone who normally holds semantic precision as
> something of uptmost importance. 

The meaning is quite clear, and quite precise.

> What are the "contents" of an ontology?

An ontology is a document.  Its contents are the contents of the document.

> Is it the RDF syntax? The triples? The abstract syntax?  The conditions
> imposed on interpretations by the syntax? 

At the level of *syntax* it doesn't matter.  All you need to do is to take
the document, in whatever form it is, and add it to the importing ontology,
in whatever form *it* is.  Then the syntax-to-semantics mapping takes
over.  

> Do you agree with Mike Smith's
> syntactic approach [1]? 

Sure, except that it runs afowl of XML junk.  

> If so, what about the issues I raised [2]? 

By treating the imported ontologies as separate documents, and doing the
syntax-to-semantics translation in that context.  Actually only the XML/RDF
to RDF graph needs to be done in context.  You could also duplicate the NS
stuff on every top-level element in the included ontology. 

> And
> finally, how is this "better" than my entailments based approach? 

Your approach requires a treatment of ontologies and imports in the
semantics, which raises big issues that I don't want to have to handle in
the semantics.

> One of
> the problems we got into with DAML+OIL is we didn't say what imports
> meant, and thus everybody interpreted it to mean whatever they felt
> like. 

Well, I think that the problem was that we thought that it was obvious what
a DAML+OIL ontology was, and thus what imports meant.

> If we cannot be perfectly clear about its meaning in OWL then we
> have failed.

Well maybe not failed, but certainly we would not have a complete success. 


> Jeff
> 
> [1] http://lists.w3.org/Archives/Public/www-webont-wg/2002Sep/0167.html
> [2] http://lists.w3.org/Archives/Public/www-webont-wg/2002Sep/0197.html

peter
Received on Monday, 16 September 2002 19:23:15 GMT

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