Re: bNodes as graph identifiers (ISSUE-131)

On Jun 1, 2013, at 1:26 PM, Andy Seaborne wrote:

> (hoping migrating of email does not cause problems)
> 
> Sandro:
>>> 
>>>> BTW: Are graph literals in N3 tidy or not?
>>> 
>>> I don't know what "tidy" means in this context.
> 
> Tidy literals means there is only one occurrence as I understand it.
> 
> :s :p "foo" .
> :t :q "foo" .
> 
> so when is "foo" tidy (as in RDF) it has incoming links :p and :q
> 
> If it were untidy, there would be two instances of "foo" in the graph

Thats impossible, in the abstract syntax. The literal *is* the node, so if they really are the same literal, then there is only one node. 

None of the rest of your message makes sense to me. 

Pat


> (mathematical sense - 2 nodes in the node set).  It affects what code can do when walking the graph node by node.  It does not affect SPARQL.  We all tend to see them as the same but (as various discussions from WG RDF-2004 seem to show), sometimes it's not.
> 
> In N3(ish) with graph literals it is more pronounced:
> 
> :s :p { :a :p :b  }
> :t :q { :a :p :b  }
> 
> is either
> 
> :s :p _:g1
> _:g1 = { :a :p :b  }
> 
> :t :q _:g2
> _:g2 = { :a :p :b  }
> 
> or
> 
> :s :p _:g1
> _:g1 = { :a :p :b  }
> :t :q _:g1
> 
> The N3 submission isn't clear to me in this area.
> 
> It is detectable.
> 
> ASK
> { :s :p ?X .
>  :t :q ?X .
> }
> 
> It may make a difference when quoting; I haven't had time to dig deep
> enough but something around:
> 
> {
>  <x> :claims _:a .
>  <y> :claims _:b .
> }
> 
> _:a { :WeatherToday :value :Sunny }
> 
> _:b { :WeatherToday :value :Sunny }
> 
> You can argue with modelling - but if :WeatherToday is a URL location whose contents changes over time, I'm maybe over simplying but if so, only in a way that people do already trip over.
> 
> Do <x> and <y> make the same claim or do that make separate claims
> containing the same information?  Maybe later different times stamps appear.
> 
> Looks a bit like stating vs statement - unclear (to me) ATM.
> 
> 	Andy
> 
> 

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Received on Sunday, 2 June 2013 05:55:44 UTC