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Re: proposed second reply to Jeremy's comment about named graphs

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 11 Sep 2013 17:43:52 -0700
Cc: RDF WG <public-rdf-wg@w3.org>
Message-Id: <5479D6CA-4ED7-48D7-8056-77C601FBD450@ihmc.us>
To: Peter Patel-Schneider <pfpschneider@gmail.com>
I like this. Is it a good idea to also refer to the notes that Sandro and Pierre-Antoine are supposed to be writing? Just to show we havnt stopped worrying about it, you understand. 

Pat

On Sep 11, 2013, at 1:28 PM, Peter Patel-Schneider wrote:

> 
> Dear Jeremy:
> 
> This is a second official response to your comment about named graphs in 
> http://lists.w3.org/Archives/Public/public-rdf-comments/2013Jul/0021.html and
> http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0005.html
> 
> 
> The RDF Working Group believes that there are several ways in which RDF
> graphs and datasets are and will be used.  These include ways that fit into
> your use cases, where the graph names denote the graph they name or some
> other formal graph-related construct and where you would indeed say
> something like
> 
> jjc:graph {
>   jjc:graph dc:creator "Jeremy J. Carroll" .
> }
> 
> However, there are also ways that do not fit into your use cases, for
> example where the graph names are IRIs that denote some other entity, such
> as
> 
> jjc:jjc {
>   jjc:jjc rdf:type foaf:Person .
>   jjc:jjc foaf:lastName "Carroll" .
>   jjc:jjc foaf:knows jjc:pfps .
> }
> 
> If the RDF semantics required that all graph names denote graph-related
> constructs this would interfere with these other use cases.  Therefore the RDF
> Working Group decided to not so require.
> 
> Further the RDF Working Group was unable to agree on even a weak theory of
> named RDF graphs, such as one conditioned on explicit typing.  Even the
> nature of what graph names might denote was problematic: does the name of an
> RDF graph denote the graph itself, does it denote some other construct that
> is related to the graph, or does it even denote the semantic meaning of the
> graph?  
> 
> Therefore the working group has produced a very minimal specification for
> RDF datasets and named graphs that does not depend on denotation.
> 
> This approach produces maximally compatability, but does not produce 
> inferences that might be desirable in some use cases.  If you do want
> certain inferences to be part of your approach, such as the first example
> above entailing  
>   jjc:graph rdf:type jjc:Graph.
> you can define and implement a particular RDF entailment regime that
> sanctions these inferences.
> 
> The RDF Working Group believes that this minimal approach will allow
> different approaches to named graphs to coexist some allowing what you want
> and others incompatible with what you want.  The flourishing approaches can
> then be considered for standardization at a later time.
> 
> 

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Received on Thursday, 12 September 2013 00:44:20 UTC

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