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Re: MT for imports (was: Re: Imports Proposal)

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 13 Nov 2002 09:56:55 -0500
Message-Id: <p05111712b9f817eba23d@[10.0.1.2]>
To: pat hayes <phayes@ai.uwf.edu>, Jeff Heflin <heflin@cse.lehigh.edu>
Cc: www-webont-wg@w3.org

Here's another one for you guys - really happened - I have two 
students who wanted their ontologies linked -  no changes involved 
but:
   A publishes P importing Q
   B publishes Q importing P
If the WG decides to go with one of these import closures things (and 
Pat's examples below show yet more reasons I worry if we've got it 
right) we need to make sure we handle cycles in some correct way.
  -JH





At 9:46 AM -0500 11/13/02, pat hayes wrote:
>Jeff, your email got me thinking about the intricacies which arise 
>when thinking about imports in the context of a changing world. Here 
>are few more example scenarios. In each case A, B, C etc are people, 
>P, Q, R, etc are chunks of OWL in documents. 'changes' means 
>altering the RDF at a given URL.
>
>1.
>A publishes P
>B publishes Q importing P
>A changes P (to P')
>C reads Q and imports P'
>
>Now, has C got it right, or not? Or should C have imported P (how?) 
>Or should B have tracked A's changes (how?)
>
>2.
>A publishes P
>B publishes Q
>C publishes R importing Q
>B changes Q to Q' importing P
>D reads R
>
>Has D got it right? This is really a special case of the first one, 
>but since the change involves an imports, the effect is magnified, 
>as it were. Obviously, the change could be arbitrarily far along an 
>imports-reference chain.
>
>3.
>A publishes P
>B publishes Q importing P
>A's server crashes
>C reads Q , concludes that the imports P is empty, archives the result
>A's server comes back online
>
>Now has C got it right? Or should C have refused to archive an 
>empty-due-to-404  imports statement?
>
>Pat
>
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-- 
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 Wednesday, 13 November 2002 09:57:02 GMT

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