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Meeting Results ( was Re: some GRAPHS strawpolls for today (agenda?) )

From: Sandro Hawke <sandro@w3.org>
Date: Wed, 25 Apr 2012 12:43:34 -0400
To: public-rdf-wg <public-rdf-wg@w3.org>
Message-ID: <1335372214.9663.370.camel@waldron>

Here's the consensus I heard during the meeting.   Obviously the minutes
will have more detail.   Maybe this is enough to guide the creation of
WD text.

> ====================================
> 
> 
> 1. The default graph is asserted
> 
>   "{<a> <b> <c>}" entails turtle("<a> <b> <c>")

Agreed, although the terminology needs to be tweaked.

> 2. Named graphs are not asserted
> 
>   "<u> {<a> <b> <c>}" does not entail turtle("<a> <b> <c>")

Agreed, with a little hesitation around the question of whether
publishing a turtle document on the Web is "asserting" it.

> 3. Named graphs are opaque
> 
>   "<u> {<a> <b> <c>}"  does not entail "<u> {<a> <b> _:x}"

It's an open question whether named graphs should be opaque or
transparent, but they should be one or the other.

> 4. Graph labels denote just like in RDF
> 
>   "{<u1> owl:sameAs <u2>} <u1> {<a> <b> <c>}"
>   owl-entails
>   "<u2> {<a> <b> <c>}"

Agreed, in broad terms that <u> as a graph label means the same thing as
<u> used as a term in an RDF triple.    Some concern about what all the
implications of this might be, and using owl:sameAs when talking about
this.

AZ proposed an example:
     gop:obama { ... bad things about this guy, gop:obama ... }
     dems:obama {... good things about this guy, dems:obama ... }
then
     gop:obama owl:sameAs dems:obama
because it is the same person.

My response was: don't do that.   Using a person as the graph label
object isn't a very good idea, and this is one of the reasons.

> 5. Blank nodes labels have file scope
> 
>    See SPARQL queries in 
>    http://www.w3.org/2011/rdf-wg/wiki/Graphs_Design_6.1#Blank_Nodes
>    or Skolemization example in
>    http://lists.w3.org/Archives/Public/public-rdf-wg/2012Apr/0132.html

Not sure.  Some agreement, and no clear disagreement, but Richard and AZ
had concerns we didn't have time to get into.

> 6. In trig, @union can be used in place of the default graph
> 
>    "@union <u> {<a> <b> <c>}" entails turtle "<a> <b> <c>"

Agreed, after being amended to clarify
  - this is TriG syntactic sugar
  - it can be used in addition to the default graph
  - the word might not be "union"

> 7. Datasets only say which triples are known to be in a named graph,
>    not which triples are *not* in that named graph.
> 
>    The merge of "<u> {<a> <b> <c>}" and "<u> {<a> <b> <d>}" is 
>    "<u> {<a> <b> <c>,<d>}".  
> 
>    Also "<u> {<a> <b> <c>,<d>}" entails "<u> {<a> <b> <c>}".

Not agreed.  Lots of confusion, especially about that last test case.

When just asked about the first test case (the merge) and thus
partial/complete semantics, or "huh???" if it wasn't clear, votes were:

<Souri> +1 to partial
<Guus_> agree with partial being the default
<ericP> complete
<ivan> +1 to partial
<cygri> probably prefer partial
<davidwood> both
<Guus_> +1
<sandro> okay with either partial or complete, not sure about both at
once
<davidwood> (at least partial)
<pchampin> +0 (have to think over)
<AndyS> "huh???" and partial (may be app choice)
<AlexHall> partial
<AZ> +1 have both with an indicator to say which
<ericP> complete for datasets, partial for trig syntax, which is
complete at the end of the document

So.   That's where we are at the moment.   

      -- Sandro
Received on Wednesday, 25 April 2012 16:43:48 UTC

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