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RE: DAMl "Thing" should be Top, Universal class - including concr ete types

From: Peter Crowther <Peter.Crowther@melandra.com>
Date: Tue, 6 Feb 2001 19:19:15 -0000
Message-ID: <B6F03FDBA149CA41B6E9EB8A329EB12D01919B@vault.melandra.net>
To: "'Deborah Mcguinness'" <dlm@ksl.stanford.edu>
Cc: RDF Logic list <www-rdf-logic@w3.org>
> From: Deborah Mcguinness [mailto:dlm@ksl.stanford.edu]
> I would posit that we have not yet seen a compelling 
> naturally occurring
> example of a need for combination of the types.

Deborah, how much control did you have over versioning within CLASSIC and
the systems you built around it?  I agree with you for CMs where there is a
centralised create-distribute-modify-redistribute approach to versioning.
*The* problem with the Semantic Web, IMHO, is going to be the same as *the*
problem with the HTML Web: no central authority can control the version of
anything that is in use.  This problem applies to standards, and gives Web
authors the world over nightmares of the
should-I-support-pre-CSS[2]-browsers kind; but, worse, it applies to
distributed models too.

At its best, this may subject us to the logical equivalent of link-rot,
where the targets of URIs are either inaccessible or deleted.  At its worst,
it leads to part of a user base describing the world using one version of a
model where (say) book titles are strings, and another part of the user base
describing the world using another (later) version of the same model where
(say) book titles are complex.  If both publish their portions of the model
using RDF, how can we reason about both at once?  Or is there a bodge that
treats the two versions as semi-independent?  Or can we not reason about
both at all?

I'm sure exactly the same problem has cropped up with XML, where the DTD
referred to in the DOCTYPE has changed since the data was created and the
data is therefore invalid.  However, I suspect the solution there ("it's
still XML, so just parse it") is not one that we can apply here.

		- Peter
Peter Crowther
Received on Tuesday, 6 February 2001 14:19:30 UTC

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