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

From: pat hayes <phayes@ai.uwf.edu>
Date: Wed, 13 Nov 2002 13:00:36 -0500
Message-Id: <p05111b09b9f843856561@[]>
To: Jim Hendler <hendler@cs.umd.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 
>   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.

Cycles should be OK as far as the MT is concerned. Actually following 
links requires care, obviously.

>  -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.
>>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?)
>>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.
>>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?
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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)

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Received on Wednesday, 13 November 2002 13:00:05 UTC

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