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Re: Contexts (not again!)

From: Graham Klyne <GK@ninebynine.org>
Date: Wed, 13 Nov 2002 12:59:54 +0000
Message-Id: <>
To: "Danny Ayers" <danny666@virgilio.it>
Cc: "RDF-Interest" <www-rdf-interest@w3.org>

I think the "dark triples" approach fizzled out.  My take is that we're not 
ready to standardize context mechanisms yet, but  still have hopes of 
prototyping my ideas in this area, which aren't vastly different from what 
I think you're describing.  I think that reification, or a variation of it, 
can be used (in a prototype implementation) to encode the triples that 
aren't asserted.

In the longer run, a standard solution may call for something more 
"hard-wired", with scope for optimization.  I think this might come about 
without invalidating/isolating the
prototype approaches.


At 10:59 PM 11/2/02 +0100, Danny Ayers wrote:

>Hi folks,
>Did any kind of consensus, or even decision (!?) result from Pat's 'dark
>triples' suggestion [1] etc. earlier in the year (or any other of the
>familiar context discussions)? I've had a look through the archives and as
>usual the threads are hard to follow. I'm wondering because I'm running up
>against this thing again.
>If there isn't anything sorted or on the cards in this area, I'd appreciate
>comments on the following first crack hackiness for a context vocabulary.
>I've not really got a grip on the reification angle with it yet, but the use
>I'm after is really just to be able to tag triples (make 'em quads in
>memory), and it'd be nice to do it in a moderately sound fashion.
>Just three terms (the pseudo-schemas are undoubtedly way out) : context,
>contains, contents
>*context* - a group of statements (identified collectively by a single URI)
>with which a particular statement can be associated. In practice this would
>usually be
>[triple]-context->[RDF file]
>Property "context"
>    domain Resource
>    range Statement
>    inverseOf contains
>*contains* - the other way around,
>[RDF file]-contains->[triple]
>Property "contains"
>    domain Statement
>    range  Resource
>*contents* - a list/collection whatever of (references to) the statements to
>be identified by a given URI (i.e. the triples in a file)
>Property "contents"
>    domain Bag
>    range Resource
>[RDF file]-contents->[s1, s2...]
>The first of these is probably all that I'd need, but the second insisted on
>coming along. The third heard there was a party.
>When I started thinking of a way around this, the first thing that came to
>mind was a Context class, akin to a collection/bag, instances of which could
>be used to identify a file but with this it seemed to get messy a lot
>I'm pretty sure I'm badly conflating the unreified/reified triples here, and
>it does seem like it goes a bit beyond what can be expressed in RDF(S) alone
>(i.e. a minilayer on top) but I'm hoping that something usable won't be far
>away. I'm willing to bet there's something along these lines already, but I
>can think of worse ways to spend a Sunday evening.
>[1] http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Mar/0253.html
>Danny Ayers
>Semantic Web Log :

Graham Klyne
Received on Thursday, 14 November 2002 07:46:34 UTC

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