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RE: Do resources have representations?

From: <Patrick.Stickler@nokia.com>
Date: Mon, 28 Jul 2003 18:03:48 +0300
Message-ID: <A03E60B17132A84F9B4BB5EEDE57957B026301A5@trebe006.europe.nokia.com>
To: <b.fallenstein@gmx.de>, <jon@spin.ie>
Cc: <www-rdf-interest@w3.org>


I've found it useful to think of URIs as being bound to
particular intensions of resources.

E.g. several URIs may all denote the same thing, i.e.

   http://example.com/MorningStar 
      owl:sameIndividualAs
         http://example.com/EveningStar ;
      owl:sameIndividualAs
         http://example.com/Venus .

but each URI, and the statements made about the resource
using that URI, are specific to a particular intension of 
the thing denoted.

It is a fact that the Morning Star and the Evening Star
are the same thing, namely the planet Venus, and that
all three names are denotationally synonymous.

However, some names carry along with them a view or
perspective or scope of knowledge that is beyond
the simple denotation.

And the sets of representations which are available via
one URI versus another can reflect the difference in 
intension.

Thus, the representations accessible in terms of the
URI http://example.com/MorningStar could include images 
of Venus at dawn whereas the representations accessible in 
terms of the URI http://example.com/EveningStar could include
images of Venus at dusk, and the representations accessible
in terms of the URI http://example.com/Venus might include
all of the above as well as sattelite and probe images,
etc.

And the maintainers of one set of representations may
have no clue about the denotational equivalence of the
URI they use with that of another URI by which someone
else maintains an entirely different set of representations.

Thus, even though many URIs may all denote the same thing
in the universe, each particular URI used can indicate an
intension that is distinct.

Cheers,

Patrick


--
Patrick Stickler
Nokia, Finland
patrick.stickler@nokia.com
 

> -----Original Message-----
> From: ext Benja Fallenstein [mailto:b.fallenstein@gmx.de]
> Sent: 28 July, 2003 17:24
> To: Jon Hanna
> Cc: www-rdf-interest@w3.org
> Subject: Re: Do resources have representations?
> 
> 
> 
> 
> Hi Jon,
> 
> Jon Hanna wrote:
> > Rather than add to the roles a URI plays like you do, I 
> prefer to pare it
> > back, and say that *the only* thing a URI does is identify 
> a resource. The
> > fact that it can be dereferenced to retrieve a representation is no
> > different to any other identifier (ISBN, Social Security 
> Number, personal
> > name etc.) given an application context which understands 
> the identifier and
> > can provide a representation.
> 
> Couple of interesting points in your mail, but for the moment 
> I'd like 
> to cut to the heart of the matter that's giving me headaches 
> and reply 
> only to this part of your mail.
> 
> Are you saying that "denote a resource" is the *only* thing 
> that a URI 
> does?
> 
> Then how can it be that two URIs that denote the *same* resource can 
> give me *different* representations when I put them into my browser?
> 
> I.e., every time I go to <http://example.org/1434> I see one 
> particular 
> page, and every time I go to <http://example.net/~foo/bar> I 
> see another 
> particular page, yet the two URIs identify the same resource.
> 
> How do you explain this?
> 
> - Benja
> 
> 
Received on Monday, 28 July 2003 11:04:04 GMT

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