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Re: Labelled graphs

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Wed, 25 Apr 2012 15:08:41 +0100
Message-ID: <4F980569.2030904@epimorphics.com>
To: Sandro Hawke <sandro@w3.org>
CC: RDF-WG <public-rdf-wg@w3.org>

On 25/04/12 14:48, Sandro Hawke wrote:
> On Wed, 2012-04-25 at 14:06 +0100, Andy Seaborne wrote:
> [taken out of order]
>> And there are other things in the charter.
> Yes, indeed.   Many of us keep saying that other things need to take
> priority, but perhaps we're not saying that loudly enough, and perhaps
> our actions (sending lots of email about graphs) speak even more loudly.
> I would support a plan to fork graphs off onto another meeting time and
> even another mailing list until there is consensus among the people
> participating in that alternative forum.

Yes, for the semantics, not the syntax which (1) is already out there 
anyway, refining details would be a step forward, and (2) ought to 
survive future changes/revisions to the semantics.  RDF is extensible in 
that way!

>>> To be clear, are you saying you would like the entirety of this WG's
>>> output concerning "named graphs" to be a Recommendation for the grammar
>>> of TriG?
>> No.  I'm suggesting we must at least provide that.  It would be a step
>> forward.
> Agreed.
>> Given the discussions, I am not convinced that fixing one semantics is
>> desirable.  I see different viewpoints, from different use cases, all of
>> which have merit.  Deciding the semantics now feels like research, there
>> not being one as input.
> To me, it feels like what we did in making RDF 2004.
> (Of course, you could say that was a mistake, but it's hard to know
> where we'd be otherwise.)
> The problem is, I think, that the only way to find out if some design
> works is to convince a lot of people to try it at the same time.   How
> can you do that?  It looks to me like the way we do that in the Semantic
> Web community is to make it a W3C Recommendation (or a least Candidate
> Recommendation).

In this case, it will be a quite long period to know if it works.  It's 
not the toolkits - it's the data publishers and data consumers, and the 
data interchange that is the test of the utility.

The context is different from RDF 2004, there was a much smaller RDF 
world then. At that time, the need was a revised standard and more risk 
was appropriate (speculative design, research, whatever you want to call 

That's not how I see things now - RDF is out there and in use by a much 
larger community. Hence do the minimum needed and separately, work on 
more.  If the proposed semantics work out, great.  If they get revised, 
why also cause the minimum (syntax, graph packaging) to also fallback?

> I suppose another approach would be to have a back-room chat amongst the
> people behind some key SemWeb tools (eg Jena).   But is that better than
> the W3C process?

It's not a reason to bypass W3C.

> We could set a very high bar for CR on this, if we
> want to make sure it doesn't get to Rec until "it actually works".
>> I think the best approach is to define the absolute minimum, and publish
>> the semantics as based on that.  This means if the semantic proposals
>> are found wanting (not in a technical sense, but in a utility sense c.f.
>> reification) others can also emerge.
>> This isn't giving up - it's realising there is a minimum and
>> possibilities on top of the core basics.
>>   >  I note that our charter says:
>>   >
>>   >           Required features
>>   >                 * Standardize a model and semantics for multiple graphs
>>   >                   and graphs stores
>> My conclusion currently is that there are different ways of using named
>> graphs in applications and they are all valuable.  The use cases are not
>> met by some common semantics choice directly.
>> Even if they can all be built on one common semantics (and this itself
>> is not obvious to me - I can see different strands still running), it
>> can still end up too complicated in practice.  So we can meet the letter
>> of the charter and still not improve the situation.
> Among the people who want to work on this, I'd like to see if we have
> consensus on a few simple bits, like the sameAs entailment test earlier
> in this thread, or the idea that the default graph is asserted.
> Maybe we can do that today, or maybe today's telecon can be spent on
> other things we need to do.

Yes but it's up to the chairs as far as I'm concerned (/me says "the 
right thing").  It might be useful for a group to go off and come back 
with a complete proposal for discussion in the WG as it may be easier 
for the wider WG to engage with a complete proposal rather than emails 
on particular points.  Maybe - different styles work for different people.


>      -- Sandro
Received on Wednesday, 25 April 2012 14:09:22 UTC

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