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Re: A triple is not unique.

From: <jos.deroo.jd@belgium.agfa.com>
Date: Mon, 20 Nov 2000 02:45:19 +0100
To: " - *seth@robustai.net" <seth@robustai.net>
Cc: " - *www-rdf-interest@w3.org" <www-rdf-interest@w3.org>
Message-Id: <0006800035296625000002L052*@MHS>
If somebody writes some document/context x containing
  <web:Describes about="uri1">
    <nsp:foo ID="y" rsource="uri2"/>
  </web:Description>
then anyone can refer to that particular statement via x#y
and make further statements about it.

I think this also implies (but is not equivalent to)
  <web:Statement ID="y">
    <web:subject resource="uri1"/>
    <web:predicate resource="nspuri#foo"/>
    <web:object resource="uri2"/>
  </web:Statement>
If we *assert* a context containing such reified statement then
we should accept that statement as if it were an axiom and then,
I think, both descriptions are equivalent.

Of course, we often want these statements to be anonymous
resources (no ID attribute).

--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/





seth@robustai.net@INTERNET@w3.org on 18/11/2000 17:56:01
Sent by: www-rdf-interest-request@w3.org
To: www-rdf-interest@w3.org@INTERNET
cc:
Subject: A triple is not unique.
The triples in my computer are different from the triples in
your computer.  If I assert to my computer:

<description about="uri1">
  <foo>uri2</foo>
</description>

I will have the triple [uri1, foo, uri2] in my computer.  If
you read the RDF statement above, you will have the same
triple in your computer. Now if I refer to a triple with the
syntax:

<description>
  <type>statement</type>
  <subject>uri1</subject>
  <property>foo</property>
  <object>uri2</object>
</description>

to which triple do I refer, mine or yours?  Obviously, I
must be referring to a class of objects with those triples
- just like when I say dog, I am referring to a class of
objects and not the particular one named Rover lounging at
my feet.  But what If I *want* to refer to a particular
triple, like I refer to Rover?  What if I want to refer to
the particular triple [uri1, foo, uri2] which also has the
triple [uri1, bar, uri3] associated with it?  Well I can't
find any way to do that in the RDF specification.  May I
propose that the best way to reify a  *particular* statement
is to give it a uri that can be dereferenced to that
particular statement.  Maybe something like the following:

<description about="uri1">
  <foo ident="stid:robustai.net#20001118a">uri2</foo>
  <bar>uri3</bar>
</description>

Now I can refer to that particular statement with:

<description about="stid:robustai.net#20001118a">
  <type>statement</type>
  <subject>uri1</subject>
  <property>foo</property>
  <object>uri2</object>
</description>

Seth Russell
http://robustai.net/~seth/index.htm
authorOf: http://robustai.net/ai/Oedipus.htm
Received on Sunday, 19 November 2000 20:45:33 GMT

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