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Re: Two questions about bagid

From: Tim Berners-Lee <timbl@w3.org>
Date: Mon, 3 Mar 2003 20:52:11 -0500
Cc: pat hayes <phayes@ai.uwf.edu>, w3c-rdfcore-wg@w3.org
To: Frank Manola <fmanola@mitre.org>
Message-Id: <EA36198D-4DE3-11D7-887D-000393914268@w3.org>

>

(with apologies, a message delayed for a few days, while my laptop was 
repaired)



> I don't necessarily mean to suggest that we go back through all this 
> again, but the pertinent threads where we discussed this were places 
> like the following, in case anyone wants to go through the archives 
> (including de re/de dicto, Superman, and the whole nine yards):
>
> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0157.html

A thread which argues philosophically about the identity of URIs but 
does not
discuss allowed entailments.

There was a lack of test case.   One test case is whether (writing = 
for daml:equivelentTo)
the following is a valid entailment:

:Superman =  :ClarkeKent.
Lois :believes :s .
:s  rdf:subject :Superman .
:s rdf:predicate rdf:type.
:s rdf:object  :Strongman.
_________________________
Lois :believes :s .
:s  rdf:subject : ClarkeKent .
:s rdf:predicate rdf:type.
:s rdf:object  :Strongman.

This follows from a current axiom of = that

{ ?x ?p ?y.  ?y = ?z } => { ?x ?p ?z }.

This settles the question as to whether quoting would matter or not.
Clearly quoting solves the problem.

:Superman =  :ClarkeKent.
Lois :believes :s .
:s  rdf:subject2 ":Superman" .
:s rdf:predicate2 "rdf:type".
:s rdf:object2 ":Strongman".

does not allow that entailment.

One has then a

Patrick and janet accepted the problem but didn't see how using literals
helped.

> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Feb/0314.html
> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Feb/0239.html
>
> --Frank
>
> -- 
> Frank Manola                   The MITRE Corporation
> 202 Burlington Road, MS A345   Bedford, MA 01730-1420
> mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-875
>
Received on Monday, 3 March 2003 20:52:13 EST

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