W3C home > Mailing lists > Public > uri@w3.org > October 2000

Re: URIs for Physical Items

From: Michael Mealling <michael@bailey.dscga.com>
Date: Mon, 16 Oct 2000 23:53:20 -0400
To: Aaron Swartz <aswartz@swartzfam.com>
Cc: uri@w3.org
Message-ID: <20001016235320.B18274@bailey.dscga.com>
On Mon, Oct 16, 2000 at 10:21:01PM -0500, Aaron Swartz wrote:
> Paskin, Norman (DOI-ELS) <n.paskin@doi.org> wrote:
> > No, URLs are not appropriate for designating physical items:
> > 1. A physical item may exist in multiple copies.  ISBNs for example do not
> > refer to a specific copy of a book; they identify the class of all copies in
> > an edition.  It is useful to identify the class not a specific instance of
> > it. 
> 
> I disagree. I may want to talk about my iBook, which is most definitely a
> specific instance of an item, and a very real one. (And whose Internet
> address is ibook.swartzfam.com.) But I could also want to talk about all
> iBooks, as a class. Both are definitely worth referring to. Are you saying
> that such references are beyond the scope of URIs?

Be very careful here guys. One of you is talking about URLs and one is
talking about the general class of all URIs...

> > 2. A user may well wish to differentiate between a website (URL) -e.g. for
> > maintenenace, administration; and the entity currently avaiulable at that
> > website.  If the URl is used for one it cannot be used for the other.
> 
> This is an interesting point. Is there a concept of a pointer, to
> distinguish between the address "http://apple.com/ibook/" (perhaps this
> could be done using the data: scheme?) the actual page currently at
> http://apple.com/ibook/ and the class of objects described at
> http://apple.com/ibook/ (namely iBooks)?

Not within the scope of URIs and their Resources, no. This is a topic that
has come up recently and has always been an interesting source of rat holes.
URIs identify Resources. If you want to specify other semantics such as
the container, the thing in the container, the class of containers, etc
then you need some relationship grammar similar to RDF that can make
these type of assertions. But please note that this is simply one
application that makes use of URIs. There are other applications that
use URIs all day long without ever getting into these complex assertions.

-MM

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Received on Tuesday, 17 October 2000 00:03:33 UTC

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