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A shot at http://www.w3.org/2000/03/rdf-tracking/Overview.html#rdfms-resource-semantics

From: Martyn Horner <martyn.horner@profium.com>
Date: Tue, 08 May 2001 09:21:26 +0200
Message-ID: <3AF79E76.4EF86D2D@profium.com>
To: w3c-rdfcore-wg@w3.org
http://www.w3.org/2000/03/rdf-tracking/Overview.html#rdfms-resource-semantics

I got back to my desk yesterday to start pondering the resource semantic
issue.

I sketched out a review of what other people have said on the subject
but then I got immersed in the discussion here on `truth' and
`provenance'.

It's clear that the definition of resource in the M&S spec is intended
to be a `fundamental' definition from which the rest can be built. It's
clear also that there's a question whether a `resource' as understood in
RDF represents the bit-sequence (or the actual atoms) of a referenced
entity or some sort of pledged token of good intent towards an
significantly-invariant object.

I wonder, given the need to emphasise the legal aspects of RDF
assertion, whether we don't need to define resources reflexively to
support this.

I was playing with a definition along the lines of `a token for an
object constrained in a set of dimensions expressed by a set of
properties and values but otherwise capable of redefinition'. There's a
musing somewhere which talks about successive degress of specificity in
a web reference. Using `isVersionOf' and `isLanguageSpecificVersionOf'
allows resources to inherent a set of dimensional constraints from
another resource or to have them selectively relaxed.

It seems to me that, to reflect the spirit of the Semantic Web, we
should help to define the handles on the system in ways that allow (and
encourage) fullfillment rather than impose limitations. Defining
resources by their role in RDF (and not RDF as a process on resources)
both expresses the spirit and allows a rigorous `external' description
of `assertion'. It means that `resources' get an RDF-specific
definition.

I guess I'm trying to permit the `resource is as resource does'
definition while explicitly allowing textual change behind the URI. URIs
need not stand for a fixed set of atoms, but they must serve to support
assertions (and essentially, only that). 

(I got caught by this this week. The page at
http://blogspace.com/rdf/mimetype got changed during the discussion
before I could read the first emails that suggested it needed changing.
Very confusing. I guess that's OK...  :-)
 
This also lets in a possibility of resource equivalence in that two URIs
could be described as equivalent (as mirrors) while physically separate.
This means that RDF could be used (must be used) to express
`canonicality' of URIs (one is the master, the other the derivative).

Please comment before I begin another spiral...

By the way,
http://lists.w3.org/Archives/Public/www-rdf-interest/2001Apr/0027.html
(by Dan Connolly) has some good sense on the subject: `URIs mean what we
all agree that they mean'

Resource identification is a `social and contractual issue'
(http://www.w3.org/DesignIssues/NameMyth). That links the two issues
nicely.
-- 
Martyn Horner <martyn.horner@profium.com>
Profium (former name Pro Solutions), Les Espaces de Sophia,
Immeuble Delta, B.P. 037, F-06901 Sophia-Antipolis, France
Tel. +33 (0)4.93.95.31.44 Fax. +33 (0)4.93.95.52.58
Mob. +33 (0)6.21.01.54.56
Internet: http://www.profium.com
Received on Tuesday, 8 May 2001 03:21:22 EDT

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