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

Re: Anonymous resource names -versus- variables

From: Graham Klyne <GK@dial.pipex.com>
Date: Mon, 08 May 2000 11:29:10 +0100
Message-Id: <4.3.1.2.20000508110623.00c002d0@pop.dial.pipex.com>
To: jos.deroo.jd@belgium.agfa.com
Cc: <www-rdf-interest@w3.org>
At 02:17 PM 5/5/00 +0200, jos.deroo.jd@belgium.agfa.com wrote:
>Graham Klyne wrote:
> > This sparks a thought for me:  RDF recognizes two "layers" of statements:
> >    statements
> >    statements about statements, via reification
> >
> > Your comments suggest another facet of RDF usage:
> >    statements about representations of statements
> >
> > I sense that some discussion of RDF gets mired because of failure to
> > distinguish between statements, and some representation thereof.  I regard
> > this as a vital distinction when considering trust representations (an
> > immediate concern for CC/PP).
> >
> > I regard RDF in terms of some homogeneous collection of statements (and am
> > thinking about building an experimental system that reflects this
> > view).  Specific statements are added to the collection via documents that
> > contain representations --in XML or whatever-- but any meaning associated
> > with a statement must stand when a particular representation in a
> > particular document is stripped away.
>
>I can feel what you mean and please try to demonstate it!
>A representation 'stands for something' and
>a statement is 'something that stands' ???

I wouldn't phrase it quite that way (too many 'stands's ;-)

I'll try and construct an example of what I was saying:

Consider maps:  the real world is continuous, and exists all together.  But 
a map describes some defined part of the world (both geographically and 
kinds of features).  One map may show the position of a place with respect 
to geographical features, and another may show its connections with respect 
to transport (e.g. street map vs Underground map of London).  I think maps 
are like documents containing (representations of) RDF statements, and the 
real world is what contains the universe of all the things described by the 
maps, and more.

Further, imagine that the London Transport authority maintain a master map 
showing where to find all the instances of Underground Maps displayed in 
the subway system, and a summary of the features contained on these 
maps.  This might be thought of as a "statement about representations of 
statements".

A statement that a map was last updated on a particular date is different 
from saying something about the place where it is posted.

Much of what we know about the real world may be conveyed by maps, but we 
need to be able to distinguish between a map and the world it 
describes.  When we destroy a map, the places it describes continue to 
exist in the same relationships to each other.  Similarly, I think that the 
logic (whatever that may be) of some collection of RDF statements should 
stand in the model and associated schema separately from any document that 
may contain (some representation of) those statements.

#g

------------
Graham Klyne
(GK@ACM.ORG)
Received on Monday, 8 May 2000 08:50:56 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:43 GMT