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Re: model theory publication draft

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Wed, 19 Sep 2001 21:07:34 +0100
Message-Id: <5.1.0.14.2.20010919205911.03a61660@joy.songbird.com>
To: Pat Hayes <phayes@ai.uwf.edu>
Cc: w3c-rdfcore-wg@w3.org
At 12:15 PM 9/19/01 -0500, Pat Hayes wrote:
>If anyone wants to focus, I'd suggest looking at the stuff on RDF 
>entailment. Here's a question that occurred to me, for example. Suppose we 
>know that
>aaa rdf:type bbb .
>and also
>bbb rdfs:subClassOf ccc .
>Now, it follows that aaa is in fact a member of the class ccc; but do we 
>want to say that this means that
>aaa rdf:type ccc
>
>must be true? If we do, that table of RDF entailment rules would need some 
>more entries. Right now it reflects the view that being in a class doesn't 
>necessarily mean having that class as a type, only having some subclass of 
>it as a type.

Hmmm...

 From above:
1.   <I(aaa),I(bbb)> in IEXT(I(rdf:type))
2.   <I(bbb),I(ccc)> in IEXT(I(rdfs:subClassOf))

 From 1. and 5th rule of RDFS interpretation:
3.   I(aaa)          in ICEXT(I(bbb))

 From 2. and 6th rule of RDFS interpretation:
4.   ICEXT(I(bbb)) subset ICEXT(I(ccc))

Then by 3 and 4:
5.   I(aaa)          in ICEXT(I(ccc))

Which is the condition for
   aaa rdf:type ccc

QED?

If I'm right, these means no change is needed unless aaa is NOT of rdf:type 
ccc.

#g


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Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
<Graham.Klyne@MIMEsweeper.com>
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Received on Wednesday, 19 September 2001 16:16:34 EDT

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