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Re: complete vs partial graph semantics

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Thu, 12 Apr 2012 16:54:53 +0100
Message-ID: <4F86FACD.6010306@epimorphics.com>
To: Sandro Hawke <sandro@w3.org>
CC: public-rdf-wg@w3.org


On 12/04/12 16:09, Sandro Hawke wrote:
> I'm having a lot of trouble understanding the motivation for
> partial-graph semantics.   It seems to me like a kind-of-cool but
> way-too-complicated idea.

Dataset merge - it's not just imperative.  It's just the conclusions of 
accepting two datasets like graph merge is accepting the conclucions of 
two graphs.

Concat TriG files.

> It's like you're saying that any triple:
>
>      <a>  <b>  7.
>
> is to be understood as saying that the value of the 'b' property of 'a'
> is not just seven, but rather it is seven-or-more.
>
> You see the analogy?

<#you> :name "Sandro" .
<#you> :name "Sandro Hawkes" .

more triples come along.

Another issue is that I don't think you can ever claim completeness 
without minting the <u>.

Consider the non-archiving crawler.  Just because it say N triples, 
don't mean there are N triples at a resource.  Security, cookies, 
location etc may give someone else a different view even of an immutable 
resource and the crawler can't know.

>   To me,
>
>     <u>   {<a>  <b>  <c>  }
>
> looks like tagging the graph {<a>  <b>  <c>  } with the label<u>; but now
> I'm being told you're actually tagging some unknown graph that happens
> to contain at least the triple {<a>  <b>  <c>  }.

That isn't what I meant by labelling.  I have so far not been able to 
work out what you mean unless it's owl:sameAs naming but we're 
considering other labellings aren't we?  It's indirect?

> So, back to the number analogy: it seems like the reason people want to
> to do this is because they sometimes want to increase the value of this
> property.   Later they might want to say it's ten-or-more.  There seems
> to be some concern that this could be a problem if we said that it was
> now exactly seven.

That's "replace" the value, not "extend" it.

RDF graphs can be merged, numbers can't.

	Andy
Received on Thursday, 12 April 2012 15:55:30 UTC

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