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Re: Named graphs etc

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 9 Mar 2004 11:08:11 -0600
Message-Id: <p06001f2bbc73a6c0d00e@[]>
To: Patrick Stickler <patrick.stickler@nokia.com>
Cc: "Pat Hayes" <phayes@ihmc.us>, <www-archive@w3.org>, <jjc@hplb.hpl.hp.com>, "ext Chris Bizer" <chris@bizer.de>

>On Mar 09, 2004, at 13:18, ext Chris Bizer wrote:
>>>Is it information, or better considered meta-information? Can the
>>>provenance info be accessed separately from the graph itself?
>Here's where I think we need to make an important distinction between
>"authoritative" qualification of a graph and third-party qualification
>of a graph.
>It may be the case that an agent trusts certain third parties, and even
>may choose to trust statements made about a graph by a third party over
>statements made about the graph in the graph itself (e.g. the owner
>of the graph specifies a higher accuracy percentage than the more-trusted
>third party, or the owner of the graph doesn't explicitly state that the
>graph is asserted but the third party does, etc.).
>Note that the ability to consider third party statements about a graph
>still doesn't preclude the need for a bootstrapping mechanism, since,
>after all, one has to determine the trust associated with the graph
>containing those third party statements as well...

Interesting thought. Let me modify my earlier suggestion, or maybe 
extend it. Asserting is publishing with a publishMode="assert" tag 
(if tag omitted, publication is assumed as a SW default, but legal 
tightness might require it).  Alternatively, one can give a URI which 
points to another document which acts as a 'publication warrant'; 
this might for example record provenance information, give security 
key information, things like that. And it can be stored on a secure 
server somewhere, safe from harm, and providing a checksum to use as 
security against malicious changes to the warranted graph. The 
publication warrant should itself have a publishMode="assert" tag on 
it, and can refer to the original graph by name, and can assert in 
RDF that it is warrant for the named graph. This would be very hard 
to fake, and can easily be made exponentially harder by adding more 
warrant layers referring to even more secure sources of 
warrantability. The very fact that the warrant URI is in a secure 
namespace uses the Web to provide a high degree of security.

Notice also that this entire thing can  be set up without any 
publication actually happening until the publishMode property on the 
warrant is set, and changing this value can 'turn off' the 
publication; so this provides a kind of trusted-third-party control 
over assertion: if you hold my warrant, then you can un-assert my 
publications.  Of course I can just not refer to your warrant, but 
then who is going to trust me?

>>I see the trust layer more as an application domain for named graphs.
>>So for defining named graphs we don't have to go too far.
>We at least seem to agree on this particular point.
>(sorry, Pat, for being in a closer timezone to Chris and pre-empting
>your right to first reply...)

S'OK, I see this as a free-for-all in any case. One of the joys of 
email is that you can interrupt without actually interrupting, if you 
see what I mean.


>Patrick Stickler
>Nokia, Finland

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Received on Tuesday, 9 March 2004 12:08:14 UTC

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