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Re: Another try.

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Tue, 21 Feb 2012 16:00:51 +0000
Message-ID: <4F43BFB3.3050308@epimorphics.com>
To: public-rdf-wg@w3.org


On 21/02/12 12:03, William Waites wrote:
> On Tue, 21 Feb 2012 11:44:56 +0000, Andy Seaborne<andy.seaborne@epimorphics.com>  said:
>
>      >  If I understand the quad proposal, then all existing
>      >  vocabularies are technically undefined because they never define
>      >  P(S,O,G), only P(S,O).
>
> Back in December, I experimented with a tuple-store that understood a
> variant of n-triples (mostly as an exercise in learning Haskell
> properly). It had datatypes of URI, Bnode, Literal and Nil and
> supported predicates of any arity.
>
> Is it useful define such a nil value and say:
>
>    For all (P, S, O), P(S,O) ->  P(S,O,nil)

Sure - I can see how it can be done if the old vocabularies are modified 
... but I'm wondering if Pat's proposal forces that modification and 
whether the explicit label+set of triples form does not.

All existing vocabularies like FOAF don't say anything about P(S,O,G) so 
if we just do it as an extension from pairs to triples (triples to 
quads), then the existing definitions that talk about pairs don't apply 
any ore do they?

Concretely:

:g1 { <x> foaf:age 15 }

:g2 { <x> foaf:age 25 }

In a graph foaf:age has a definition (albeit troublesome)..

> Does this connect to SPARQL's idea of a default graph in a useful way?

Wasn't on my mind as such.

>
> -w

	Andy
Received on Tuesday, 21 February 2012 16:01:20 UTC

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