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Re: rdf11-concepts WD ready

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 29 May 2012 20:05:09 -0500
Cc: RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <78DB39C1-65D1-4BC3-91B9-4656A579BC1E@ihmc.us>
To: Richard Cyganiak <richard@cyganiak.de>
More.

3

"bijection" seems a bit heavy-mathematical for a primer (?). Maybe spell it out in more detail?

3.3
"a datatype IRI being an IRI that establishes the literal value."

Slightly misleading, could be read as saying that the datatype IRI alone determines the value. Maybe re-word like
"a datatype IRI being an IRI that determines how the lexical form maps to the literal value."

3.4 

"The blank nodes in an RDF graph are drawn from an infinite set. "

This seems a rather odd way to introduce the idea. I know it is formally correct, but it reads (to me) rather jarringly. (Which set? Why that set in particular? Etc..) 

Suggest something more like:

"A blank node is a node which has no associated information or structure. In an RDF graph, a blank node represents an 'unknown' entity which may not have a name. In the abstract syntax, we specify only that blank nodes are taken from a fixed infinite set which is disjoint from the set of all IRIs and the set of all literals."

also 3.4

"Given two blank nodes, it is possible to determine whether or not they are the same."  

Um. I know I am always being acussed of thinking like a mathematician, but this doesn't make sense as stated. If there are TWO blank nodes, then obviously they aren't the same, because if they were there would only be one of them. I know it is hard to say this without using words like "identity", so I suggest simply omitting this sentence altogether, and rephrase the paragraph as something like

"RDF makes no reference to any internal structure or syntactic form of blank nodes. A blank node is simply a node in an RDF graph which has no label or other structure relevant to its RDF role."

3.5

"This transformation does not change the meaning of an RDF graph, provided that the Skolem IRIs do not occur anywhere else."

(I know we agreed on this wording long ago, but...) You might add something like 

"It does however permit the possibility of other graphs subsequently using the IRI to also refer to the same entity, which was not possible when the node was blank."

5. 
"The lexical-to-value mapping of a datatype is a set of pairs whose first element belongs to the lexical space of the datatype, and the second element belongs to thevalue space of the datatype:

	 Each member of the lexical space is paired with (maps to) exactly one member of the value space."

Why not bite the bullet and actually say that it is a functional mapping, or even that it is a function?  You do that for the datatype maps in 5.4 and it reads very naturally.

Pat


On May 29, 2012, at 5:34 PM, Richard Cyganiak wrote:

> In case anyone wants to have a last-minute check of the RDF Concepts draft before it goes out for publication:
> http://dvcs.w3.org/hg/rdf/raw-file/rdf-concepts-WD2/rdf-concepts/index.html
> 
> The publication date is still preliminary.
> 
> Best,
> Richard
> 
> 
> 

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Received on Wednesday, 30 May 2012 01:05:48 GMT

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