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Re: Dark triples, current closure / entailment rules, can someone clarify?

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 25 Jun 2002 18:58:34 -0500
Message-Id: <p05111b19b93eb358bf5f@[65.217.30.113]>
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Cc: w3c-rdfcore-wg@w3.org

>At 10:19 AM 6/25/02 -0500, pat hayes wrote:
>>I fail to follow why this kind of example would lead you to that 
>>conclusion. BUt in any case there are other strong reasons for not 
>>coming to that conclusion, which we have gone over now several 
>>times. If there is any way to assert darkness, then there is no 
>>way, in practice, to avoid nonmonotonicity. ...
>
>You say _no_ way, but I thought that a syntax extension (in the 
>graph syntax) was a possibility.

Well, what I meant by _no_ was that if there is any way at all of 
asserting it, then someone somewhere is going to hack a way of not 
asserting it, and then someone else is going to find a way to add it, 
and then....

I guess I have great respect for the creativity of users to find a 
way to break almost any spec that is breakable. For evidence, read 
the recent thread on RDF logic about how to provide urirefs for graph 
arcs. For more evidence, consider the fact that the Stanford DAML 
reasoning engine has an (illegal, but..) 'unassert' command built 
into it.

>I agree it has the other disadvantages you mention, but I want to be 
>clear what our *possible* choices are.

Well, I guess it depends on how cynical you are :-)

Pat
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Received on Tuesday, 25 June 2002 19:58:37 EDT

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