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Re: Using rdf reification to nest statements in N3 like contexts

From: Graham Klyne <GK@NineByNine.org>
Date: Sun, 17 Mar 2002 14:17:56 +0000
Message-Id: <5.1.0.14.2.20020317140550.00a02b60@joy.songbird.com>
To: "Seth Russell" <seth@robustai.net>
Cc: "RDFIG" <www-rdf-interest@w3.org>
At 08:06 AM 3/16/02 -0800, Seth Russell wrote:
> > I was presuming a very general technique:  one "enters" a context by
> > performing one level of "unreification" -- create a new graph with each
> > rdf:Statement resource in the context generating a statement (triple)
> > containing the corresponding subject, object and property.  Using my
> > scheme, inner nested contexts still appear as reification quads.  The top
> > level statements of the context entered come out as (non-reified)
> > statements, hence asserted.
>
>Well I don't see how this works in any practical manner because  you could
>only access a particular context via the expression tree in which it was
>entered.  How could you say arbritrary things about arbritray context nodes
>?

You need additional machinery to define "lifting rules", which tell you how 
to how and when to transfer the truths you get by entering one context into 
another context -- I suppose you could view this as a kind of cross-context 
entailment.

The main thrust of my note [1] was to try and codify, in terms of 
relationships between the interpretations in a "context structure", some 
simple patterns of contexts in a way that could lead to some simple lifting 
rules.  Although I've hinted at some patterns, they are far from being 
nailed down and I think there will always be the possibility of additional 
patterns:  I don't expect a single definitive answer for every possible use 
of contexts.

>... anyway did I get the mentograph of your proposal right?  The ded arc
>from C to the inner nested context labeled with the Bnode _:4 would, imho,
>not show up correctly.

I'm sorry, but the mentograph didn't "speak to me" (I don't know how to 
interpret it), so I can't answer that.  I prefer to try and use (albeit 
imperfectly) the language that is used more generally in the field of KR, 
as that helps me to leverage some work that has been done.

#g

[1] http://www.ninebynine.org/RDFNotes/UsingContextsWithRDF.html



-------------------
Graham Klyne
<GK@NineByNine.org>
Received on Sunday, 17 March 2002 10:14:13 GMT

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