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Re: LANG: need to CLOSE Issue 5.6 Imports as magic syntax

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Thu, 7 Nov 2002 12:53:52 +0000
Message-ID: <15818.25184.252599.558377@merlin.horrocks.net>
To: Jeff Heflin <heflin@cse.lehigh.edu>
Cc: Jim Hendler <hendler@cs.umd.edu>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, www-webont-wg@w3.org

I am happy with the solution proposed by Peter and Jeff - i.e.,
extra-logical imports statements with closure.

I agree with Jeff that this is essential in any "industrial strength"
ontology language. In realistic cases users will want to modularise
their ontologies and in a given application explicitly state which
modules they are using (or "committing to" if you like). They will
need to know that these modules will be used, and no other modules
(unless explicitly imported by some module). I don't see how they can
do that by just allowing applications to "follow their nose".

I'm not sure how substituting the mentioning of terms is going to work
in this context. What if I have an ontology module X that introduces
various properties and another module Y that just contains axioms
asserting properties of these properties (transitivity, inclusion
etc.). I want to include the Y axioms in my ontology, but there isn't
anything in there to mention.


On October 31, Jeff Heflin writes:
> Jim (and others)
> Those of you who read my discussion with Tim should realize that the
> solution he proposed was that if a document mentions a term from a
> namespace, that the statements from that namespace should be merged with
> the document when processing (essentially this an implict imports). I
> admitted that in the example I described, this would work (but only as a
> workaround, it would force people to design ontologies in a certain way
> to take advanatage of this behavior). Note, though to have any semantic
> interoperability, this behavior would have to be stated as <em>part of
> our semantics.<em> If we chose to do this, then it would also have the
> side effect that we would then not be able to add on the ability to
> "import parts of ontologies" because by default, simply mentioning a
> term from an ontology implicitly imports the whole thing.
> Jeff
> Jim Hendler wrote:
> > 
> > [various stuff snipped]
> > 
> > I've been avidly following this discussion, and also carefully read
> > the dialog between Jeff and Tim Berners-Lee publicly logged at [1].
> > I find myself torn - on the one hand, I'm certainly familiar with
> > Jeff's work in SHOE and the use of something like "imports" to mean
> > "Commits to" -- i.e. that I agree with EVERYTHING that some ontology
> > (or set of instances or whatever) says, whether I link to it directly
> > or not. On the other hand, I'm beginning to better understand what
> > Dan (and Tim) are saying about maybe we want to allow more freedom to
> > explore different commitment methods and the like.
> > 
> > I would ask the following - if imports is an optional feature (we've
> > already agreed it doesn't have to be used), and since anyone can
> > invent their own term to explore a different commitment strategy what
> > is the downside of including an imports statement of the type Jeff
> > advocates?)
> > 
> > For example, I am playing with something that looks a bit like this:
> > 
> >   <> jim:commits
> >     [jim:partialMappingTo foo: ;
> >      jim:usingMappingRules bar: ] .
> > 
> > in some recent research, and don't see where the existence of
> > imports, which I won't use here, bothers me.  I couldn't live with
> > the meaning that referring to something in another ontology
> > automatically had the strong implication that imports does (total
> > agreement), but I have no real problem with one I don't have to use,
> > but can if I want that particular meaning.
> > 
> > So Dan, I guess this is to you -- why do you think including one
> > particular imports method would be premature standardization?  Would
> > it help if we made sure that documents (all or some) made it very
> > clear that this use of imports was optional?
> >   -JH
> > 
> > p.s. This is not meant to be rhetorical, I'm really trying to
> > understand both sides.
> > 
> > [1] http://ilrt.org/discovery/chatlogs/rdfig/2002-10-30.html
> > --
> > Professor James Hendler                           hendler@cs.umd.edu
> > Director, Semantic Web and Agent Technologies     301-405-2696
> > Maryland Information and Network Dynamics Lab.    301-405-6707 (Fax)
> > Univ of Maryland, College Park, MD 20742          240-731-3822 (Cell)
> > http://www.cs.umd.edu/users/hendler
Received on Thursday, 7 November 2002 07:54:37 UTC

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