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Re: Strawpoll proposals on terminology

From: Peter Frederick Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 13 Oct 2011 07:44:44 -0400
Message-ID: <20111013.074444.2172981499651866496.pfps@research.bell-labs.com>
To: <ian.davis@talis.com>
CC: <public-rdf-wg@w3.org>
From: Ian Davis <ian.davis@talis.com>
Subject: Strawpoll proposals on terminology
Date: Wed, 12 Oct 2011 16:22:20 -0500

> I think we would get understand the extent of consensus in the group if we ran
> some strawpolls on usage of our terminology with some concrete statements
> 
> I restated some definitions from SPARQL 1.1 using explicit RDF Graph and RDF
> Container terminology. I also extended the idea of explaining in prose what
> certain SPARQL queries mean. I finally threw in a few statements that push the
> boundaries of what we discussed today.
> 
> S0) The state of a Graph Container is an RDF Graph.
> 
> S1) A Graph Store contains one (unnamed) slot holding a default Graph Container
> and zero or more named slots holding named Graph Containers.
> 
> S1a) A Graph Store contains one (unnamed) default Graph Container and zero or
> more Graph Containers each associated with a IRI.
> 
> S2) An RDF Dataset is a set { G, (<u1>, G1), (<u2>, G2),... (<un>, Gn) } where G
> and each Gi are RDF Graphs and each <ui> is an IRI.
> 
> S3) The RDF Graphs in an RDF Dataset are the states of the Graph Containers
> contained in the Graph Store.
> 
> The following all assume <g> is associated with a Graph Container in the Graph
> Store
> 
> S4) When we write SELECT * WHERE { GRAPH <g> {?s ?p ?o} } we mean the SPARQL
> engine should retrieve the RDF Graph that is the state of the Graph Container
> that <g> is associated with and evaluate the graph pattern against the RDF
> Graph.
> 
> S5) When we write INSERT DATA { GRAPH <g> { :s :p :o } }  we mean the SPARQL
> engine should retrieve the RDF Graph that is the state of the Graph Container
> that <g> is associated with, perform an RDF-Merge operation between that RDF
> Graph and :s :p :o and set the state of <g> to be the resulting graph.
> 
> S6) When we write DELETE DATA { GRAPH <g> { :s :p :o } } we mean the SPARQL
> engine set the state of the Graph Container that <g> is associated with to the
> empty RDF Graph

So far so good.

S7 is an attempt to push the metatheory of graph containers into an RDF
theory.  I am not convinced that this is a good idea.

> S7) When we write SELECT * WHERE { GRAPH <g> {?s ?p ?o} } the triple <g>
> rdf:type :GraphContainer is true for some <g>
> 
> S7a) When we write SELECT * WHERE { GRAPH <g> {?s ?p ?o} } the triple <g>
> rdf:type :GraphContainer is true for all <g>

S8 pushes a much-too-strong notion of the abiogenesis of RDF graphs.

> S8) When ASK WHERE { GRAPH <g> { :s :p :o } } evaluates to true and <g> is an
> http IRI then at some time in the past an HTTP GET request to <g> has returned a
> document that when parsed results in a graph that contains the triple :s :p :o
> 
> --
> Ian Davis, Chief Technology Officer, Talis Group Ltd.
> http://www.talis.com/ | Registered in England and Wales as 5382297
> 

peter
Received on Thursday, 13 October 2011 11:45:53 GMT

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