W3C home > Mailing lists > Public > www-rdf-interest@w3.org > May 2000

Re: lightweight reification

From: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
Date: Wed, 31 May 2000 09:32:17 +0200
Message-ID: <3934C001.B9429A26@bat710.univ-lyon1.fr>
To: Graham Klyne <GK@Dial.pipex.com>
CC: RDF interest group <www-rdf-interest@w3.org>
> Pierre-Antoine CHAMPIN wrote:
> >Why should we make a difference between reifying a triple and reifying an arc,
> >that is :
> >
> >  ___________
> >| S -(P)-> O|         S -(P)-> O
> >|___________|             |
> >       |              (assertedBy)
> >  (assertedBy)             |
> >       |                   v
> >       v                Someone
> >    Someone
> >
> >    (fig 1)              (fig 2)

> Fig 2 can be treated as a convenient shorthand for S-(P)->O, PLUS its
> reification, PLUS the arc 'assertedBy' from the root resource of the
> reification to 'Someone'.

that's not a shorthand, that's the way I understand what you describe !
Everyone seems to consider a triple reification as the frame in fig.1,
I consider a triple reification as the arc itself,
because reifying it (i.e. "making it a thing") is necessary to draw another arc from it.

As I write, it occurs to me that the fram is useful when the reified triple is not asserted,
but when it is, fig.2 looks equivalent to fig.1 (IMHO), and much more intuitive.

> I happen to quite like the direct arc-from-property approach,

so do I :)

> but it's not RDF as we know it.

I still think this is a "perception issue"

> The recent posting about:
>     <property rdf:ID="id">...
> suggests a way of representing this, which would map into a formal model
> consisting of quadruples -- almost the same as RDFM&S, section 5, except
> that the set called 'Statements' consists of quadruples of the form:
>    {pred,subj,obj,ID}

SiRPAC already uses this syntax, without using 4-uples :
the rdf:ID in a property tag causes it to reify the triple,
and assigns a user-defined URI to the reified triple,
instead of assigning it a system-generated URI.

This fits entirely the current RDF model.


--- Quid quid Latine dictum sit, altum viditur
    Whatever is said in Latin sounds important.
Received on Wednesday, 31 May 2000 03:23:22 UTC

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