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RE: Indicating Closure ("and that's all there is")

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 07 Dec 2001 07:52:12 -0500
To: SCranefield@infoscience.otago.ac.nz
Cc: sandro@w3.org, www-rdf-interest@w3.org
Message-Id: <20011207075212S.pfps@research.bell-labs.com>
From: Stephen Cranefield <SCranefield@infoscience.otago.ac.nz>
Subject: RE: Indicating Closure ("and that's all there is")
Date: Fri, 7 Dec 2001 14:33:51 +1300 

> Sandro Hawke wrote:
> > RDF has an "anyone can say anything about anything" philosophy that
> > seems deeply at odds with the practical need to list a specific set of
> > properties and by omission negate all others.  If I'm listing my car
> > for sale in RDF, I can list the repair work that has been done to it,
> > but I cannot say that this is all the repair work.
> 
> ...
> 
> > I'd rather just find a way to say "and that's all" or "here's the edge
> > of the world", but I don't know how to do that. 
> > 
> > Has anyone solved this problem?  
> 
> In my paper "UML and the Semantic Web" at
> http://www.semanticweb.org/SWWS/program/full/paper1.pdf (Section 5)
> I proposed the use of a property notClosedOn defined as follows:
> A statement <p, notClosedOn, r> is a declaration that there may
> exist some statements <r, p, r'> that are known to hold but which
> aren't included in the model.  The absence of a notClosedOn statement
> means that it can be assumed that complete information is given for
> property p applied to subject r.  An equally viable alternative
> approach would be to assume that all information is *incomplete*
> except where a ClosedOn statement specifies otherwise.
> 
> This is similar to mechanisms in knowledge representation systems
> such as LOOM and CLASSIC, and to "local closed world" formulae in AI
> planning.  

Well, perhaps a very tiny bit similar.  However your formulation is a
closed-world assumption method to relax the closed-world assumption. The
formulation in CLASSIC is an construction to augment a knowledge base with
(current) autoepistemic information.

The mechanism in CLASSIC is precisely a way of saying ``and that's all
here''.

> - Stephen

peter
Received on Friday, 7 December 2001 07:53:14 GMT

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