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Re: a question about RDF reification

From: David Allsopp <d.allsopp@signal.qinetiq.com>
Date: Tue, 25 Jun 2002 14:40:20 +0100
Message-ID: <3D1872C4.980BBCCF@signal.qinetiq.com>
To: www-rdf-logic@w3.org



"Peter F. Patel-Schneider" wrote:

> Suppose you have an XML/RDF document that uses reified statements and
> doesn't use rdf:ID for resources or rdf:bagID.  (This qualification is to
> get around the fact that rdf:ID for resources and rdf:bagID implicitly
> involve rdf:Statement.  It could be relaxed by essentially modifying the
> expansion of these constructs.)
> 
> If you change rdf:Statement to RDF:STATEMENT in the document has anything
> really changed as far as RDF is concerned?  If you think that something
> important has changed, what is it?  If you think that nothing has really
> changed, then what role was reification playing in the document?

As far as RDF is concerned, nothing of substance has changed, because
RDF does not appear to place any real restrictions on the Statement
construct. I guess one could answer "yes, those nodes are no longer
rdf:Statements" but in practice this makes no difference within RDF - an
RDF engine is not required to handle Statement nodes differently from
any other nodes, AFAIK.

However, as far as software handling the document is concerned,
everything might break.

For example, if I have an application that reifies every statement in
order to attach a timestamp, I will probably run into problems; there is
nothing special about the rdf:Statement, but it does form a unique
marker for Statements.

I guess this problem would occur in any logic where call-outs to special
code are used, e.g. to handle geospatial or temporal values in a
general-purpose logic? i.e. the special code ('outside' the logic) is
dependent on specific vocabulary inside the logic?

Regards,

David Allsopp.

-- 
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Received on Tuesday, 25 June 2002 09:42:10 GMT

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