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Re: RDF vocabulary definitions

From: Jeen Broekstra <jeen.broekstra@aidministrator.nl>
Date: Tue, 19 Nov 2002 20:43:29 +0100
Message-ID: <3DDA9461.9020104@aidministrator.nl>
To: "Richard H. McCullough" <rhm@cdepot.net>
CC: Jon Hanna <jon@spin.ie>, www-rdf-interest@w3.org

Richard H. McCullough wrote:

> The rdf-mt document http://www.w3.org/TR/2002/WD-rdf-mt-20021112/
> says in Appendix A, "RDF Axioms":
>     rdf:type(?x,?y)  iff  ?y(?x)
> The triple translation is
>     <?x> <rdf:type> <?y>  iff  <?x> <rdfs:subClassOf> <?y>
> The KR translation is
>     $x has type = $y  iff  $x isa* $y

Looking at section 3.3 of the MT, you seem to be correct, though this is
not reflected in the RDFS entailment rules in section 4.

Section 3.3 (RDFS Interpretations):

   <x,y> is in IEXT(I(rdfs:subClassOf)) if and only if x and y are in IC
   and ICEXT(x) is a subset of ICEXT(y)


   <MyClass, rdfs:Class> is in IEXT(I(rdfs:subclassOf)) if and only if
   1.  MyClass and rdfs:Class are in IC
   2.  ICEXT(MyClass) is a subset of ICEXT(rdfs:Class)

Condition 1 is trivially met. Condition 2 is met because ICEXT(MyClass) 
is the empty set.

It's late and I'm tired. Am I overlooking something, or is this a bug?

Best regards,

Received on Tuesday, 19 November 2002 14:43:35 UTC

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