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Re: Proposed response to Golbeck regarding imports issue

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 17 Jun 2003 10:41:54 -0400 (EDT)
Message-Id: <20030617.104154.82874163.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: Proposed response to Golbeck regarding imports issue
Date: Tue, 17 Jun 2003 09:44:05 -0400

> Peter,
> 
> I expect that there will be many OWL applications that arbitrarily
> collect together a set of OWL documents and then reason over their
> conjunction. 

If you removed the first ``OWL'' from the above sentence, I would agree
with you wholeheartedly.

> If we could not do this then OWL would be of limited use,
> because the only things we could combine would be things that were
> explicitly identified as imported by the original authors of the
> documents (so much for serendipitous discovery :-<). 

I am certainly not arguing that the above is prohibited in any way by any
of the OWL documents.  I am only arguing that doing so is not supported by
the OWL spec, and, because of this, the OWL documents should not encourage
this any more than any other action that is not supported by the OWL spec.

> Now, I agree that
> any conclusions made are not necessarily entailed by any one document in
> the collection, and thus the person or software tool that combines the
> documents must take full responsibility for any conclusions drawn. A
> formal way to view such process is think of a virtual OWL document that
> simply imports all of the documents in the collection (similar to what
> Ian suggested Dan do, but I am suggesting that you do not have to create
> a series of bytes that corresponds to this document).  

One might want to think this way, and it might be useful to describe the
actions of a tool in this way, if only to describe part of what the tool is
doing in terms of the OWL spec.  However, the tool is going beyond the
spec.

> The parenthetical
> remark that you oppose is there to indicate that tools are free to
> collect any set of documents they wish, combine them, and even do OWL
> reasoning on the combination. 

Just as tools are free to do anything that they want.  However, I do not
see any reason for the OWL documents to single out this particular
extension above other useful extensions. 

> For these reasons, I find the comment
> helpful to readers, especially those who like Dan and Jim, want to
> experiment with alternatives to imports. 

If people want to experiment with alternatives, then they should feel free
to do so even in the absence of any indication in the OWL documents.  They
should, however, be very explicit that their alternatives are not part of
the OWL spec, and the OWL documents should not do anything to encourage any
mistaken belief that these alternatives are part of the OWL spec.

> Jeff

peter



> "Peter F. Patel-Schneider" wrote:
> > 
> > From: Jeff Heflin <heflin@cse.lehigh.edu>
> > Subject: Proposed response to Golbeck regarding imports issue
> > Date: Mon, 19 May 2003 13:28:52 -0400
> > 
> > >
> > > The following is a proposed response to Jennifer Golbeck regarding the
> > > issue with imports raised in:
> > >
> > > http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0068.html
> > >
> > > Dear Jennifer,
> > 
> > [...]
> > 
> > > First you discuss the following passage from the reference document,
> > > 7.3:
> > >
> > > "Note that the importing a document is different than creating a
> > > namespace reference. owl:imports do not set up a shorthand notation for
> > > names as does a namespace reference. On the other hand, the namespace
> > > reference does not imply that all (or even any) ontological terms from
> > > that namespace are being imported. Therefore, it is common to have a
> > > corresponding namespace declaration for any ontology that is
> > > imported."
> > >
> > > You are correct that there are a few problems here: First, we are
> > > inventing the term "namespace reference" when we mean "namespace
> > > declaration." Second, the point of this paragraph was to comment on why
> > > namespace declarations and imports are both needed, not to comment on
> > > how systems might follow links. In particular, we were trying to say
> > > that they are very different animals. I suggest the following rewording:
> > >
> > > "Note that although owl:imports and namespace declarations may appear
> > > redundant, they actually serve very different purposes. Namespace
> > > declarations simply set up a shorthand for referring to identifiers.
> > > They do not implicitly include the meaning of documents located at the
> > > URI (although some applications may choose to process these documents in
> > > addition to the original document). On the other hand, owl:imports does
> > > not provide any shorthand notation for referring to the identifiers from
> > > the imported document. Therefore, it is common to have a corresponding
> > > namespace declaration for any ontology that is imported."
> > 
> > [...]
> > 
> > I oppose including the parenthetical remark above.  I believe that such
> > permissive statements have no place in our documents.
> > 
> > Peter F. Patel-Schneider
> > Bell Labs Research
> > Lucent Technologies
Received on Tuesday, 17 June 2003 10:42:10 GMT

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