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Re: Dark triples are not inherently nonmonotonic

From: Jim Hendler <hendler@cs.umd.edu>
Date: Thu, 30 May 2002 19:46:43 -0400
Message-Id: <p05111745b91c6a4295c4@[10.0.1.4]>
To: "Jonathan Borden" <jonathan@openhealth.org>, "WebOnt WG" <www-webont-wg@w3.org>
Cc: "pat hayes" <phayes@ai.uwf.edu>, <guha@guha.com>

John - w/due respect, did you mean this for WOWG or for RDF-logic, 
which is where that was posted.
  -JH


At 7:17 PM -0400 5/30/02, Jonathan Borden wrote:
>Pat, did you reall write:
>http://lists.w3.org/Archives/Public/www-webont-wg/2002May/att-0302/00-part ?
>
>Now I agree that the mechanism you proposed to indicate darkness e.g.
>
>owl:List a owl:Dark
>
>is problematic from a monoticity perspective, but to suggest that
>
>[[
>  but the exact details do not matter to the point being made here.
>]]
>
>and that _dark triples themselves are inherently nonmonotonic_ is going a
>bit to far, eh?
>
>For example than triples, are rather than dark, let's consider: colored
>triples, and so a triple becomes a quad:
>
>subject predicate object color .
>
>where color is a URIref just like the others.
>
>Now assume that for all current RDF documents, the parser generates a color
>rdf:White, which corresponds to an asserted triple in the MT.
>
>Now suppose that the color of the triples (really quads but go with this),
>is a function of some attribute on the <rdf:RDF> root element of any RDF
>document e.g.
>
><rdf:RDF color="red">
>     <rdf:Description rdf:ID="foo">
>         <ex:shape rdf:resource="#square">
>     </rdf:Description>
></rdf:RDF>
>
>which generates the following N-Quad:
>
><#foo> ex:shape <#square> rdf:red .
>
>of course the color doesn't need to be rdf:red, but could be any URI, but
>that really doesn't matter.
>
>So what could possibly be nonmonotonic about that?
>
>Now assume that dark triples are triples with the color rdf:black.
>
>Are you really suggesting that triples are monotonic, but quads are
>_inherently nonmonotonic_ ? Surely not.
>
>So, as with everything, the exact details do matter to the point being made
>here, and to suggest that dark triples are inherently nonmonotonic can only
>be true if your specific definition of what a dark triple is and how it is
>created causes the nonmonotonicity.
>
>Jonathan


-- 
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, 30 May 2002 19:47:25 GMT

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