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"Schemas and Namespaces" section from 1999 RDF REC

From: Dan Connolly <connolly@w3.org>
Date: Wed, 03 Sep 2003 13:07:41 -0500
To: public-sw-meaning@w3.org
Cc: "Ralph R. Swick" <swick@w3.org>, Dan Brickley <danbri@w3.org>, Brian McBride <bwm@hplb.hpl.hp.com>, Eric Miller <em@w3.org>
Message-Id: <1062612460.572.564.camel@dirk.dm93.org>

The 1999 RDF Model and Syntax Recommendation had
a section...


2.2.3. Schemas and Namespaces
When we write a sentence in natural language we use words that are meant
to convey a certain meaning. That meaning is crucial to understanding
the statements and, in the case of applications of RDF, is crucial to
establishing that the correct processing occurs as intended. It is
crucial that both the writer and the reader of a statement understand
the same meaning for the terms used, such as Creator, approvedBy,
Copyright, etc. or confusion will result. In a medium of global scale
such as the World Wide Web it is not sufficient to rely on shared
cultural understanding of concepts such as "creatorship"; it pays to be
as precise as possible.

Meaning in RDF is expressed through reference to a schema. You can think
of a schema as a kind of dictionary. A schema defines the terms that
will be used in RDF statements and gives specific meanings to them. A
variety of schema forms can be used with RDF, including a specific form
defined in a separate document [RDFSchema] that has some specific
characteristics to help with automating tasks using RDF.

A schema is the place where definitions and restrictions of usage for
properties are documented. In order to avoid confusion between
independent -- and possibly conflicting -- definitions of the same term,
RDF uses the XML namespace facility. Namespaces are simply a way to tie
a specific use of a word in context to the dictionary (schema) where the
intended definition is to be found. In RDF, each predicate used in a
statement must be identified with exactly one namespace, or schema.
However, a Description element may contain statements with predicates
from many schemas. Examples of RDF Descriptions that use more than one
schema appear in Section 7.
  -- http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/#schemas

The RDF Core WG is doing a pretty major rewrite of that spec;
some related material ended up in a last call draft

  4.2 Social Meaning

as a result of

  Issue rdfms-assertion: RDF is not just a data model; an RDF statement
is an assertion.

but as a result of a last call issue

The WG has since decided[11Jul] to remove that section


I wonder what, if anything, we're losing in the process, and 
if something should take its place, perhaps in the webarch

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 3 September 2003 14:07:41 UTC

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