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Re: Two questions about bagid

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Tue, 11 Feb 2003 22:46:22 +0000 (GMT)
To: Tim Berners-Lee <timbl@w3.org>
cc: RDF Core <w3c-rdfcore-wg@w3.org>, www-rdf-comments <www-rdf-comments@w3.org>
Message-ID: <Pine.GSO.4.44.0302112242000.8655-100000@mail.ilrt.bris.ac.uk>

On Tue, 11 Feb 2003, Tim Berners-Lee wrote:

> Another question is about the semantics.
> I understand that an id  :i  on the statement  { :superman :can :fly}
> should generate the statements
>
> :i a rdf:Statement;  rdf:subject :superman;   rdf:predicate :can;
> rdf:object :fly.
> :superman :can :fly.
>
> and I might want to use this to generate attribution:
>
> :lois :thinks :i.
>
> This would suggest that an owl reasoner (say) that knows that :superman
> and
> :clarkekent are daml:equivalent should be able to infer that
>
> :i a rdf:Statement;  rdf:subject : clarkekent;   rdf:predicate :can;
> rdf:object :fly.
> : clarkekent :can :fly.
> :lois :thinks :i.
>
> This seems counterintuitive, as one would expect it allow one to
> conclude
> that the modified statement is due to the original source.
> Some form of quoting around the subject, predicate
> and object would seem necessary.
>
> I have been guilty of ignoring this rather complicated bit of the spec,
> and wonder whether others have done the same.
>
> A developer.

I've had this conversation with Danbri before. The owl reasoner you
posit has superman and clarkkent denoting the same thing (ie, it applies
an interpretation that a comic reader would agree with). Strictly
speaking, from the comic reader's point of view (ie, in that
interpretation) the conclusion is correct: Lois thinks that the person
denoted by "Clark Kent" can fly, which he can, 'cause he's super.

Lois wouldn't reason using the same interpretation, so her conclusions
would be different.

-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/
I am now available for general use under a modified BSD licence.
Received on Tuesday, 11 February 2003 17:49:23 GMT

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