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Re: RDF Semantics: datatype entailments

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 24 Feb 2003 14:37:02 -0600
Message-Id: <p05111b51ba80323e7bb4@[10.0.100.86]>
To: herman.ter.horst@philips.com
Cc: www-rdf-comments@w3.org

>RDF Semantics document,
>last call version, 23 january 2003
>This comment was mailed earlier to the WebOnt WG [1].
>
>
>Section 4.3, Datatype entailments
>This section only describes closure rules.
>However, I would like to suggest that more can be said.
>
>For each recognized datatype x  (that is, if x is in D)
>the following triple is D-entailed already by the empty RDF graph:
>   name(x) rdf:type rdfs:Datatype .
>
>This follows from the assumption on D-interpretations that
>D is a subset of ICEXT(I(rdfs:Datatype)).

Well yes, but there is a circularity here, since the notion of 
'recognized' only makes sense relative to some assertions of this 
precise form. That is, one asserts that a datatype is 'recognized' by 
writing a triple of the form

  name(x) rdf:type rdfs:Datatype .

so of course, *in all models of this assertion* , this assertion is 
true, ie entailed by the empty graph. While technically correct, this 
is rather a misleading way of characterizing the situation, seems to 
me :-)

Pat


>Herman ter Horst
>Philips Research
>
>[1] http://lists.w3.org/Archives/Public/www-webont-wg/2003Feb/0313.html


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Received on Monday, 24 February 2003 15:37:12 GMT

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