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Re: RDF Concepts - What is a Node?

From: Richard Cyganiak <richard@cyganiak.de>
Date: Tue, 29 May 2012 18:56:01 +0100
Cc: Dan Brickley <danbri@danbri.org>, "Peter F. Patel-Schneider" <pfpschneider@gmail.com>, RDF WG <public-rdf-wg@w3.org>, David Wood <david@3roundstones.com>
Message-Id: <2ABA24F3-27DF-4F1F-A700-4530A2E16552@cyganiak.de>
To: nathan@webr3.org
On 29 May 2012, at 08:30, Nathan wrote:
> What do we call the thing which is the conjunction of the set of statements/assertions for a node within an RDF Graph then?

I tend to use phrases like this (obviously not formally defined, but reasonably accurate):

If talking about the graph level:

“the triples having (the node/IRI/blank node) as their subject”
(if I only talk about “outgoing” arcs)

“the triples involving (the node/IRI/blank node)”
(if talking about outgoing and incoming arcs)

If talking about the domain level:

“the statements about (the resource/thing)”
(if I only talk about the meaning of the “outgoing” arcs)

“the statements involving (the resource/thing)”
(if talking about the meaning of outgoing and incoming arcs)

“a description of (the resource/thing)”
(very informally; could include additional triples beyond those immediately connected to the resource)

> the CBD?

The CBD is different depending on blank nodes/IRIs and is actually very rarely used in practice.

> It seems like a rather large concept which goes strangely undefined / unnamed in the RDF specs - and the original reason for the mail. I wrongly termed it the "node" in my original mail which led to some confusion, and if I'm getting confused / don't know what to call this concept which is pretty pivotal to RDF usage, then I'd suggest it may be useful to define / provide for others.

This concept doesn't play a significant role in any spec I'm aware of.

It plays a role in some implementations, but often inappropriately (e.g., incoming arcs are omitted for no good reason, crippling the implementation).

If I needed to make up a term for it, I'd probably call it a “node description” and carefully define it. A node description would essentially be isomorphic to a set of triples that all share the same subject.

Received on Tuesday, 29 May 2012 17:56:36 UTC

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