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Meaning of an RDF document: issue rdfms-assertion

From: Tim Berners-Lee <timbl@w3.org>
Date: Fri, 16 Nov 2001 16:43:21 -0500
Message-ID: <000701c16ee7$b6be9a90$84001d12@w3.org>
To: <www-rdf-comments@w3.org>
It is important that the specification (at W3C) of a language
ground the meaning of a document written in that language
in terms of a technical specification.

In the case of RDF, there is a key step, well 3 key steps
in the meaning of an RDF document which pass through the
RDF and RDFS specs.  Most of the meaning is then defined
by the specfications of various terms in ontologies. But
it is important that the three steps below are not omitted
from the RDF specification.


1.  The meaning of an RDF document is the sum
 (in english, strictly conjunction) of the independent meanings
 of the statements of which the RDF document is comprised.

 (Here we are talking about an RDF document which contains
  directly.  RDF embedded in XML or anything else
  only has meaning in as much as it
  is given meaning by the specification of the language which
  envelops it.)

2. The meaning of an RDF statement is defined by the
  preciate used, and so is specified by the specification
  of the Property that is used as predicate.

3.  When the predicate of  statement is rdf:type, then the
  meaning of the statement is defined by the class used
  as object, and so is specified by the specification of the
  class.

They are obvious if you think about it, and represent how the
world actually works.  It is important to emphasize that in RDF
one cannot, for example, define a special object which modified the effect
of the predicate.  (By contrast, you can define in XML a new attribute
which negates the effect of a tag... and then define a new tag which
works un-negated even with the attribute and so on.  There are
no axioms.)

(Note that there is no meaning here associated with RDF embedded in random
XML.  I think this needs to be addressed. You actually need a schema or
document annotation language  to be able to get over this where you want to.
So if you have a longer term issues list then that should be on it.)

KUTGW

Tim Berners-Lee

PS: This, with a couple of other things,  was discussed on #rdfig today.
http://ilrt.org/discovery/chatlogs/rdfig/2001-11-16.html#T18-19-35
Received on Friday, 16 November 2001 16:43:30 GMT

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