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RE: TDL conflicts with the "duh!" requirement

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 25 Jan 2002 19:09:09 -0000
To: "Dan Connolly" <connolly@w3.org>, "RDF core WG" <w3c-rdfcore-wg@w3.org>
Message-ID: <JAEBJCLMIFLKLOJGMELDEENPCCAA.jjc@hplb.hpl.hp.com>

Dan:
> Brace yourself for mind-bogglinly deep
> formal argument:
>
> premise:
> 	<http://www.w3.org/> dc:title "W3C".
> conclusion:
> 	<http://www.w3.org/> dc:title "W3C".
>
> That's it.*
>

IMO we want this case to hold, but that it is not necessarily the case that
we always want "W3C" = "W3C".

For instance, if we allow literals as subjects, and say use xml:lang to
generate triples (which I think some members of the group would like) then
in general a string in one lang is not the same as the same string in
another lang.

There is also my example where the string "100" in a context in which base
10 is understood is different from the string "100" in which base 2 is
understood.

More strictly I should say 'the interpretation of the string "100" is
different'.

Now, Dan's example is interesting because the two contexts are identical and
hence the entailment is desired.

This looks quite like the bNode case

<http://www.w3.org/> dc:title _:a.

entails

<http://www.w3.org/> dc:title _:b.

(Dan's example is only interesting when the two nodes labelled "W3C" are
different).

Thus I think the patch to the TDL model theory is likely to change the
interpretation of literal nodes (Unicode string nodes) to be like that of
bNodes: i.e. involving an existential qualifier. This is likely to be over
the possible literal-value pairs that meet the type and string constraints.

I will work on it next week.

Jeremy
Received on Friday, 25 January 2002 14:09:11 EST

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