W3C home > Mailing lists > Public > www-rdf-interest@w3.org > April 2001

Re: N3 contexts vs RDF reification

From: Seth Russell <seth@robustai.net>
Date: Wed, 25 Apr 2001 07:47:11 -0700
Message-ID: <003201c0cd96$9d3bbbe0$b17ba8c0@c1457248a.sttls1.wa.home.com>
To: "Lee Jonas" <lee.jonas@cakehouse.co.uk>, "RDF-IG" <www-rdf-interest@w3.org>
From: "Lee Jonas" <lee.jonas@cakehouse.co.uk>

> I like the concept, but does it mean n+1 tuples? e.g.:
> (stmtid1,p,s,o)
> (stmtid2,references,ctx1,stmtid)

Yes, but I don't see that as a problem, do you?

> Also, you have to explicitly identify all statement occurrences
> consistently, even across documents - this could prove yet another problem
> for generating valid rdf.

Well actually I am not proposing any changes in RDF\XML  or the RDF data
model whatsoever - so my proposal would have nothing to do with validating
RDF.  Rather my proposal addresses the internal data structure of a
application ... I guess you could call it the RDF API.

> Rather than an 'artificial key' for statements, what if the key were
> regarded as (p,s,o)?
> then
> (c1,p1,s1,o1)
> (c2,p1,s1,o1)
> represents two contexts referring to the same statement.  The consumer of
> statements is free to 'import' them into their own contexts if they wish:
> (c3,p1,s1,o1).

Cool!  I hadn't though of that.  In this regard our proposals are almost
identical.  And in my application I actually do form the key p+s+o to insure
that a potentially new triple does not already exist before I store it in
the database enforcing the idealistic view that triples are unique.

However, the extra tangible arc label assigning the triple to a context
proves useful for other reasons in my system.  With it one can talk about a
statement being in a context ... and that statement being in a context ...
and so on .. and so on .. and so on.   With your system there is no such
explicit arc of which we can speak.

And also I don't understand how you have solved the reification problem ....
[previously you mention]
> It seems to me that the goal of reification is to make further statements
> about statements - i.e. make statements the subject or object of other
> statements.

I can see how we can use your technique to make statement(s) the subject or
object of other statements.  But what about just one statement ?  For
example I can say (c1,p1,s1,o1) and (c1,p2,s2,o2) and then talk about those
with (c2,p3,c1,o3) but what if I just want to talk about the second
statement alone .. how would I do that?

thanks for the dialogue ...
Received on Wednesday, 25 April 2001 10:50:45 UTC

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