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Re: Can a property not have a uriref?

From: Sandro Hawke <sandro@w3.org>
Date: Tue, 17 Sep 2002 10:52:07 -0400
Message-Id: <200209171452.g8HEq7i14766@roman.hawke.org>
To: Murray Spork <m.spork@qut.edu.au>
cc: www-rdf-interest@w3.org

> I had assumed that all predicates must be named by some uriref - this 
> seems obvious where a predicate appears in a simple s o p triple.
> But today I thought of another possible counter example (where we are 
> dealing with reification) that may actually make sense in some 
> circumstances.

Actually, there are lots of times when it makes sense to have arcs
without URIRef labels, even without reification.  Two that come to
mind are Currying and using properties when you only know their
unambiguous properties.

> Is this allowable/ make sense? If affirmative - then a property need not 
> have a uriref?

It makes perfect sense, but as far as I know it is not legal in RDF
M&S or in the new RDF Core WG drafts.  This bothers some of us, but
there are trade-offs.  I write my code to not rely on this artificial
restriction, but maybe there are good reasons to rely on it.

> BTW - "Property" and "predicate" appear to be used interchangeably - are 
> they the same concept?

As I understand it, a Property object acts as a predicate in an RDF
statement.  I can kind of imagine using a Property as something else,
or using something else as a predicate, but I think the distinction
seems to cause more confusion than it's worth.

      -- sandro
Received on Tuesday, 17 September 2002 10:52:06 UTC

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