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Re: [Editorial] "blank nodes do not denote specific resources"

From: Eric Prud'hommeaux <eric@w3.org>
Date: Thu, 19 Jul 2012 07:13:21 -0400
To: Nathan <nathan@webr3.org>
Cc: David Booth <david@dbooth.org>, public-rdf-comments <public-rdf-comments@w3.org>
Message-ID: <20120719111317.GB11192@w3.org>
* Nathan <nathan@webr3.org> [2012-07-18 22:24+0100]
> David Booth wrote:
> >On Wed, 2012-07-18 at 14:02 -0400, David Booth wrote:
> >>http://www.w3.org/TR/rdf11-concepts/#resources-and-statements
> >>says: "blank nodes do not denote specific resources".  I don't
> >>think
> >>that is quite correct, since a blank node *does* denote a specific
> >>resource.  It just doesn't give that resource a name that is meaningful
> >>outside the graph.  I suggest rewording this as "blank nodes do not have
> >>stable names that can be referenced outside of the graph".
> >
> >Andy explained off list that this was worded this way to avoid implying
> >that a bnode implies a unique, identifiable individual, since a bnode is
> >like an existential variable.  My concern was that it should be clear
> >that when someone writes (in the same graph):
> >
> >  _:b1 a :Dog .
> >  _:b1 :name "Rex" .
> >
> >both statements (when applied) refer to the *same* (unspecified) dog,
> >which has (for the purposes of this graph) been called _:b1, though
> >there may be more than one dog that satisfies these statements.  So I
> >guess the wording here is tricky, and I'm unsure of how to make it
> >clearer.
> >
> >How about "blank nodes do not indicate unique, identifiable resources"?
> >Would that be better?  I'm okay with leaving it as is if you think not.
> "blank nodes indicate the existence of a thing, without providing a
> name for that thing."


doesn't get involved in assumptions of uniqueness which exist at the
graph-level (e.g. SPARQL) but not in RDF-Entailment or OWL.

Received on Thursday, 19 July 2012 11:13:56 UTC

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