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Re: [ALL] Agenda 20 April Telecon

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Tue, 19 Apr 2011 11:15:41 +0100
Message-ID: <4DAD60CD.5030301@epimorphics.com>
To: public-rdf-wg@w3.org


On 19/04/11 10:19, Steve Harris wrote:
> On 2011-04-18, at 21:37, David Wood wrote:
>
> > Please see:
>>
>> http://www.w3.org/2011/rdf-wg/wiki/Meetings:Telecon2011.04.20
>
> I think it's worth appending Sandro's description of the .well-known
> prefix to the skolemisation proposal.
>
> I left it outto save space, and because it was fresh in most people's minds anyway.

You had to be there!

>
> - Steve
>

Trying to be clear about the details for myself, I gathered together the 
emails and minutes:

Final proposal from the minutes 14/April:

----------------

PROPOSED: If systems are going to reveal Skolemized bnodes, without 
doing damage to the graph, they MUST use a fresh URI (per bnode) and 
SHOULD follow the form
   http[s]://[domain]/.well-known/genid/[locally-uniq-id][#]
or
   tag:[domain],[year]/.well-known/genid/[locally-unique-id]
(or, someday, genid:...). Such IRIs are considered more disposable.

"genid" to be reg'd with IETF.

----------------

Observations:

1/ Why is
   http://host.com/.well-known/genid#1816
excluded?

2/ The authority is not optional in http URIs (RFC 2616 sec 3.2.2).


A skolemized bNode might look like:

http://host.com/.well-known/genid/cb48cfae-6a5d-11e0-ba3a-00270e03441

   (that's using a version 1 UUID)

tag: can be used when machines don't know their own external name (e.g. 
on a 10.* network).


Subsequent email (key parts):

On 16/04/11 15:46, Steve Harris wrote:

 > My suspicion is that the only way forward would be some text along
 > the lines of: [with apologies for any abuse of terminology]
 >
 > Systems wishing to skolemise bNodes, and expose those skolem
 > constants to external systems (e.g. in query results) SHOULD mint
 > fresh a "fresh" (globally unique) URI for each bNode.
 >
 > All systems performing skolemisation SHOULD do so in a way that they
 > can recognise the constants once skolemised, and map back to the
 > source bNodes where possible.
 >
 > Systems which want their skolem constants to be identifiable by other
 > systems SHOULD use the .well-known URI prefix.
 >
 > - Steve

On 16/04/11 18:51, Steve Harris wrote:
 > We will have to register the "genid" .well-known tag in any case,
 > and tag: might have to be amended to say that .well-known is reserved 
 > there too.

On 16/04/11 23:27, Pat Hayes wrote:
 > It is not enough that *they* can so recognize it. It needs to be
 > globally recognizable by any system that has access to the
 > specifications. We need to specify how this can be done.


I don't worry about dereferencability so prefer "genid:" -- currently 
provide support for <_:...> to put bNodes in a different space to URIs 
while reusing/abusing the syntax.

	Andy

FYI:

Registry for well-known:
http://www.iana.org/assignments/well-known-uris/well-known-uris.xml

Registration list:
http://www.ietf.org/mail-archive/web/wellknown-uri-review/current/maillist.html
Received on Tuesday, 19 April 2011 10:16:14 GMT

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