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   Re: [xml-dev] URIs are simply names was: Re: [xml-dev] "Abstract" URIs

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John Cowan <jcowan@reutershealth.com> writes:

> if someone queries the semantic web "Does
> http://www.ccil.org/self.xtm#self contain 32
> characters?" the answer would be "No", since John
> Cowan is not representable in characters.

That's right.  John Cowan is *a* character.  (:^)

But seriously, folks, in Topic Map-land, a single
addressable character, in a single specific place,
could be used as a surrogate for John Cowan.

> TM and RDF are equivalent in power.

Yes and no.  Since TMs can be expressed in RDF, you're
right, and what you say is strictly true.  However, it
takes a lot of RDF statements to make a single TM
assertion.  So the normal, predictable way of
understanding your statement that "TM and RDF are
equivalent in power" would be incorrect.

I would argue that, in the realm of the Semantic Web
and collaborative work, the TM-enhanced way of using
RDF offers a certain vital power that RDF by itself
does not offer.  TMs offer a way for semantic nets to
be self-maintaining in such a way that everything that
might someday be regarded as substantive has already
been reified.  This means that the addresses of
knowledge-bearing relationships don't pop into
existence when somebody decides to say something about
them.  And that means that, when the address of a piece
of knowledge is expressed in terms of the arc
traversals that get you there, such address expressions
don't lose their value just because someone added
knowledge to the net.  It's hard to overstate the
importance and value of this difference between the TM
way of using RDF to make assertions, and the
just-plain-vanilla RDF way of making assertions.

[Jonathan Borden:]
> > The term "subject" is in grave danger of becoming
> > as overloaded as "resource"

> "[A] subject is anything whatsoever, regardless of
> whether it exists or has any other specific
> characteristics, about which anything whatsoever may
> be asserted by any means whatsoever."
> 	--the XTM specification

> So a subject is a resource and vice versa.

The Web world's omnivalent use of the term "resource"
has created a monumental level of confusion among

* a piece of information, 

* the piece of information at a particular address, 

* the ideas the piece of information conveys,

* the non-information thing that a piece of information
  at a particular address is used as a surrogate for,

* the information or non-information thing that a piece
  of information at no particular address (i.e., a
  name) is used as a surrogate for.

These things are all different from each other, and if
we really want to communicate with each other, these
differences matter very much.

Topic Maps makes a big distinction between "subject"
and "resource."  In Topic Maps land, these terms are
not equivalent.

-- Steve

Steven R. Newcomb, Consultant

voice: +1 972 359 8160
fax:   +1 972 359 0270

1527 Northaven Drive
Allen, Texas 75002-1648 USA


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