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Re: Semantics doc now in shadow TR space

From: Graham Klyne <GK@NineByNine.org>
Date: Mon, 16 Dec 2002 11:08:16 +0000
Message-Id: <>
To: pat hayes <phayes@ai.uwf.edu>
Cc: w3c-rdfcore-wg@w3.org

Concerning:  http://www.coginst.uwf.edu/~phayes/RDF_Semantics_finalCall_2.html

At 03:12 PM 12/15/02 -0600, pat hayes wrote:
>Datatype clashes are the only inconsistencies recognized by this model 
>theory. The definition of entailment means that a D-inconsistent graph 
>D-entails any RDF graph; however, it will usually not be appropriate to 
>consider such 'trivial' entailments as useful consequences, since they are 
>not valid rdf- or rdfs- entailments.

I'm puzzled by the use of "inconsistency" here .. my understanding is that 
technically, the concept of consistency depends on negation, which is not 
recognized in RDF.

[From Metalogic, Geoffrey Hunter:
"A system S is Simply Consistent iff for no formula A of S are both A and 
the negation of A theorems of S."  He then goes on to define absolute 
consistency for systems with the possibility to express negation of any 

My take on this had been that a D-inconsistent graph is unsatisfiable.

Ah, I see you're using a different definition of inconsistency 
So my comment becomes simply:  your definition of inconsistency seems to 
be, er, "inconsistent" with some other published definitions.


Graham Klyne
Received on Monday, 16 December 2002 08:11:12 UTC

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