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Hidden triples and self-description

From: Mark Baker <distobj@acm.org>
Date: Sat, 13 Sep 2003 01:30:17 -0400
To: www-rdf-interest@w3.org
Message-ID: <20030913013017.A7027@www.markbaker.ca>

Greetings,

I have an observation to make about self-description and RDF, and some
related questions.

First, let me define a "hidden triple" to be a triple which is not
extractable from a document by an RDF processor.  A trivial example is
this; 

:myProperty rdfs:domain :myClass .
:some-object :myProperty :some-other-object .

where one hidden triple (are there more?) would be;

:some-object rdf:type :myClass .

As a REST fan, I'm always on the lookout for things that appear
non-RESTful, and I believe this may be one, as that triple is not
visible to either intermediaries nor the recipient, unless they also
know RDF Schema (this isn't RDF Schema specific, of course).

Is this a problem?

From a REST POV, which prescribes self-descriptive messages, I think
it is.  It seems to me that if there's a disconnect between what the
sender intends to communicate (which may or may not include the hidden
triple), and what the recipient or intermediaries understands them to
be communicating, then there is a failure to communicate.

Using that example above, one way to make it self-descriptive, such that
the hidden triple is not hidden, would be to use an RDF Schema specific
media type.  There are pros and cons to this approach, and I have some
ideas that could make this quite attractive - but I'll save them for
another time.

Another would be if it was the intent of the sender to not attempt
to communicate the hidden triple.  This, I'm quite fuzzy about; what
does it mean that a sender wants to communicate, versus not, a hidden
triple?  Does it suffice to say that no sender should ever intend to
send a hidden triple?

So, is this well worn territory that I haven't been exposed to, or
perhaps something that merits a closer look by those who know a whole
lot more about Semantic Web underpinnings than I do?

Thanks.

Mark.
-- 
Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Received on Saturday, 13 September 2003 01:28:50 GMT

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