Re: datasets mean their default graphs?

On Jun 20, 2013, at 6:28 AM, Andy Seaborne wrote:

> On 20/06/13 07:43, Pat Hayes wrote:
>> Have we agreed on Sandro's idea for the meaning of a datastore to be
>> that of its default graph? I would like to add this paragraph to
>> Semantics, section 10:
>> 
>> <p>If a dataset is published as an assertion then it MUST be
>> interpreted to be an assertion of its default graph. Semantic
>> extensions MAY impose extra conditions which require other named
>> graphs to be interpreted in particular ways. </p>
>> 
>> Pat
> 
> Something needs to be said that structural bnode-isomorphism and the meaning of the dataset are now separate issues, unlike graphs.

Hmm. You may be right, but Im not sure exactly what your point is with these examples.
> 
> # Dataset D1 - links to bnode graph
> { :s1 :observed _:a }
> _:a {:s2 :p2 456 }
> _:b {:s2 :p2 123 }

But does it link to the graph? Unless we stipulate this, it doesn't. And I thought that the WG had not accepted the idea of making such a stipulation for blank nodes when it is not generally true for IRIs, as it would be "too confusing". So this is NOT a link from the default graph triple to the named graph. 

> 
> # Dataset D2 - same meaning as D1, no such link
> { :s1 :observed _:z }
> _:a {:s2 :p2 456 }
> _:b {:s2 :p2 123 }

Same meaning as D1, period. Neither of them have a link.

> 
> # Dataset D3
> { :s1 :p _:z }
> <g> {:s2 :p _:z }
> 
> # Dataset D4 - same meaning as D3, bnode not now shared
> { :s1 :p _:a }
> <g> {:s2 :p _:z }

True, but this is not the same (isomorphic) dataset. THe meaning of the default graph, on one hand, and the overall structure of the dataset, on the other, are two different topics. I guess that was your point, maybe? 

Pat

> 
> 	Andy
> 
> 

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Received on Thursday, 20 June 2013 17:22:20 UTC