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Re: Comment on the Dataset proposal (syntax)

From: Richard Cyganiak <richard@cyganiak.de>
Date: Thu, 26 Apr 2012 17:28:16 +0100
Cc: RDF WG <public-rdf-wg@w3.org>
Message-Id: <87D5DB37-8337-43C9-9490-1B2FA570FA0A@cyganiak.de>
To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
Hi Antoine,

Thanks for the review.

But I'm not sure what version of RDF Concepts 1.1 you're reviewing. Since the last published WD is from August 2011, please review only the ED:

On 26 Apr 2012, at 16:30, Antoine Zimmermann wrote:
> "The RDF data model expresses information as graphs consisting of triples with subject, predicate and object."
> "The RDF data model expresses information as RDF Graphs consisting of a set of triples with subject, predicate and object."

This already says “RDF graph” in the ED.

> The word "graph", in the RDF specifications, should never appear alone like this. It is well known that a graph is a pair (V,E) where V is a set of vertices and E is a set of edges. This is not what RDF Graphs are. RDF Graphs are not graphs, in any of the accepted mathematical definition of the term. We already agreed that the word "graph" alone is ambiguous and we resolved to use the phrase "RDF Graph" whenever we talk about sets of triples.

I agree that “RDF graph” should be preferred over “graph”, and the current ED intentionally refers quite consistently to “RDF graphs”.

On the other hand, I refer you to Section 1.1, which justifies the use of the term “graph”:

A set of such triples is called an RDF graph. This can be illustrated by a node and directed-arc diagram, in which each triple is represented as a node-arc-node link; hence the term “graph”.

> "Often, one wants to hold multiple RDF graphs and record information about each graph, allowing an application to work with datasets that involve information from more than one graph."
> "... each RDF Graph, ... than one RDF Graph."

I'll appeal to editorial discretion. The sentence starts with “RDF graphs”; there's no potential for misunderstanding if we call it “graphs” a few words later.


> add "The default graph MAY be empty."

Reasonable, although redundant. I added it.

> Maybe a definition for "named graph" could be given before the formal definition of RDF Dataset:

Yes, the current ED already does this.

Your other comments are about phrases that no longer appear in the ED or have changed significantly.

I also don't want to spend too much time wordsmithing Section 6, since the design is not yet WG-approved and the terminology and definitions are still subject to change.

Thanks again,
Received on Thursday, 26 April 2012 16:28:50 UTC

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