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Re: Why empty named graphs make sense

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 29 May 2012 20:36:51 -0500
Cc: RDF-WG <public-rdf-wg@w3.org>
Message-Id: <B8CCCE41-5B72-46E1-9B6D-5FA3548E2DBF@ihmc.us>
To: Andy Seaborne <andy.seaborne@epimorphics.com>

On May 16, 2012, at 11:33 AM, Andy Seaborne wrote:

> 1/ Scenario:
> 
> A site publishes a page, in RDFa, with triples in it.
> 
> The site replaces that page, with one saying, "changes in progress, please come back later" with no triples.
> 
> Recording this seems like a reason to have empty named graphs.

To me, this seems like an argument for graph containers that can be empty. But to say that a container is empty is not the same as saying it has an emptiness in it. 

> 
> 2/ The default graph can be empty.

It can be missing. It is optional. But again. not being there is not the same as being the empty set. 

So to me, neither of these seem convincing. 

Pat


> 
> 3/ A point made has been that N-quads can't represent an empty named graph.
> 
> A syntax fix could be:
> 
> _ <http://space> .
> 
> or other style indicate a space name.
> 
> 
> To my reading, the spaces document works if "quads" are removed, not that I'm suggesting that.
> 
> How about defining as a convenience of useful vocabulary rather than core definition?
> 
> 	Andy
> 
> 

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Received on Wednesday, 30 May 2012 01:37:46 GMT

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