W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > March 2003

williams-01, proposal take 2

From: Graham Klyne <gk@ninebynine.org>
Date: Fri, 14 Mar 2003 17:27:09 +0000
Message-Id: <5.1.0.14.2.20030314171424.02d47100@127.0.0.1>
To: RDF core WG <w3c-rdfcore-wg@w3.org>

Following today's telecon, here's a retry:

Stuart's comment (2) in:

   http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0238.html

revisits the question of whether URIs *label* graph nodes, or *are* graph 
nodes.

I propose that this issue is addressed by following the terminological 
approach suggested by Pat in another message:
   http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Feb/0152.html

Specifically:

(1) the description of an RDF graph at:
   http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-concepts-20030117/#section-Graph-syntax
is (already) consistent with this view

(2) the text in section:
   http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-concepts-20030117/#section-URI-Vocabulary
needs reworking to be consistent

(3) per Pat's suggestion, we add an explanatory note in:
   http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-concepts-20030117/#section-rdf-graph
noting that the term 'node' is used to describe a subject or an object, and 
that a URIref used as such *is* a node (as opposed to a node label, or some 
other not-a-node thing associated with a node).

(4) check that other uses of the term "node" in all documents is consistent 
with this usage.

...

That's the proposal.  I remain slightly concerned that the description of a 
bnode:
   http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-concepts-20030117/#section-blank-nodes
may not be sufficently clear to non-mathematical persons.  I think it's 
mathematically clear that, though lacking visible labels, bnodes have 
identity and different bnodes may be distinguished, and a single bnode may 
appear in more than one subject or object position in a graph, but it's 
easy to get confused.

Maybe, add something like this explanatory text to the definition?:

[[
A bnode has no discernable structure other than, given two bnodes, it is 
possible to determine whether or not they are the same.  (For the purpose 
of representing RDF graphs as text, bnodes may be assigned arbitrary labels 
so that different bnodes may be distinguished;  such labels are simply a 
means of representation and are not part of any RDF graph in which the 
bnode appears.)
]]

#g


-------------------
Graham Klyne
<GK@NineByNine.org>
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Friday, 14 March 2003 12:43:14 EST

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