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Re: RDF 1.1 Semantics

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 13 Mar 2013 08:15:51 -0500
Cc: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>, RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <C09E2022-19BF-4BD9-8AD5-C8880D2795CF@ihmc.us>
To: Antoine Zimmermann <antoine.zimmermann@emse.fr>

On Mar 13, 2013, at 5:29 AM, Antoine Zimmermann wrote:

> Pat, Peter,
> 
> 
> Before sending the details of my review, these are necessary changes that must be done before publication as FPWD:
> 
> 1. remove all the statements about scope in section "Notation and terminology" and
> 2. revert to the semantics of blank node from RDF Semantics 2004, that is,
> """
> If E is an RDF graph then I(E) = true if [I+A](E) = true for some mapping A from the set of blank nodes in E to IR, otherwise I(E)= false.

But that does not jibe with our decision that blank nodes are shared between graphs in a dataset. By taking this decision, we have introduced wider-than-graph bnode scopes, in effect, even though perhaps not explicitly. The semantics needs to have this made explicit, as I am sure you will appreciate.

> """
> 
> or possibly:
> 
> """
> If E is an RDF graph then I(E) = true if [I+A](E) = true for some mapping A from the set of blank nodes to IR, otherwise I(E)= false.

That second option does not make sense and would completely change the entailments of all RDF graphs. 

> """
> 
> If these changes are not made, I will object to the publication of RDF 1.1 Semantics as a FPWD. This is not negotiable.

But it may be put to a vote :-)

> 
> Of course, this does not mean that I will block any further changes to these sections, nor that there cannot be eventually a discussion on scope in Semantics.

I would like the material on scope (perhaps with wording changes) to be put into Concepts, which is where it belongs. And we have had quite a lot of WG discussion about bnode scopes. 

> 
> I will provide a detailed review with rationale for this, but for the moment, it suffices to say that RDF 1.1 Semantics does not provide a semantics for what's defined in Concepts. Rather, it specifies a semantics for its own conception of what RDF should be.

RDF is what will be described by all the normative documents in the eventual suite. None of them are more authoritative than any others, though obviously we need to make sure that they are all aligned. RIght now, Semantics goes beyond Concepts by defining bnode scopes, but it does not contradict anything in Concepts. 

Pat



> 
> 
> -- 
> Antoine Zimmermann
> ISCOD / LSTI - Institut Henri Fayol
> École Nationale Supérieure des Mines de Saint-Étienne
> 158 cours Fauriel
> 42023 Saint-Étienne Cedex 2
> France
> Tél:+33(0)4 77 42 66 03
> Fax:+33(0)4 77 42 66 66
> http://zimmer.aprilfoolsreview.com/
> 

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Received on Wednesday, 13 March 2013 13:16:28 UTC

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