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Re: Labelled graphs

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 16 Apr 2012 08:14:06 -0400
To: Andy Seaborne <andy.seaborne@epimorphics.com>
Cc: public-rdf-wg@w3.org
Message-ID: <1334578446.2482.45.camel@waldron>
On Mon, 2012-04-16 at 13:07 +0100, Andy Seaborne wrote:
> 
> On 15/04/12 15:57, Sandro Hawke wrote:
> > On Sat, 2012-04-14 at 20:35 +0100, Andy Seaborne wrote:
> >> On 13/04/12 11:33, Steve Harris wrote:
> >>>> Read that as rdf:aaa to avoid natural language meaning.
> >>> I don't get that, but…
> >>
> >> Natural language can be confusing.
> >>
> >> <u>  rdf:label G .
> >>
> >> so is<u>  labelled by G ?
> >>      "<u>  has a label of G"
> >>      "G is a label for<u>"
> >>
> >> or is<u>  labelling G ?
> >>      "<u>  is a label for G"
> >>      "G has a label of<u>"
> >>
> >> (sometimes it does not matter -- e.g. sameValue).
> >>
> >> "labelled graphs" is more of the style"<u>  is a label of G".
> >>
> >> All that is needed as the most basic building block is a neutral
> >> association of (<u>, G) and that within a dataset (<ui>, Gi) is
> >> functional from<ui>  to Gi : given a label, find the associated graph.
> >
> > With these looser semantics, I don't think it needs to be functional.
> > Rather, I think we can define it as labeling the associated graph and
> > each of its subgraphs.
> >
> > There would be some kind of deep equivalence between these two datasets:
> >
> > D1:
> >     <u>  {<a>  <b>  1 }
> >     <u>  {<a>  <b>  2 }
> > and
> > D2:
> >     <u>  {<a>  <b>  1,2 }
> >
> > The SPARQL semantics might written in terms of a normal form, where a
> > term is only used as a label once, but the other forms would be valid in
> > trig and in the RDF Semantics.
> 
> In earlier threads, the proposal was that a TriG document had one graph 
> per label but (syntax) it may be split into separate sections for 
> practical reasons.

Yes, it was.  I'm suggesting it makes sense to put that in the semantics
of datasets, instead, so we can use this for merging datasets.  It makes
merging datasets the same as concatenating trig files (give or take
@prefix declarations and blank-node labels).

    -- Sandro
Received on Monday, 16 April 2012 12:14:22 UTC

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