Re: Named graphs etc

* Pat Hayes <phayes@ihmc.us> [2004-03-12 13:31-0600]
> 
> >I have serve problems with the idea that an agent owns a graph. Nobody owns
> >the english sentence "Water is blue.", thus I think it is also impossible 
> >to
> >own a graph expressing this sentence.
> >
> >I think we are mixing the agent/assertion/content- and the
> >representation/document document layer here again.
> >
> >I would see it this way:
> >
> >1. Graphs exist in an abstract way somewhere, similar to english sentences
> >abstractly existing somewhere even if nobody expresses them.
> >2. Agents can assert/deny/quote graphs, which takes place on the
> >agent/assertion/content-layer. Similar to me agreeing with or denying the
> >sentence the "Water is blue." Thus an assertion is the relation between an
> >agent and an abstract graph.
> >3. An agent can publish his assertion on the document layer. This "web act
> >of publication" might have a "owner" but doesn't have to. I'm thinking of a
> >graph been published as a document, then crawled and moved into a
> >knowledgebase by somebody else, who makes the graph accessible afterwards
> >though a web query interface. I think this process definitifly requires all
> >asserting- and provenance information been on the
> >agent/assertion/content-layer and not linked in any way to the document
> >layer.
> >
> >Taking the idee that a graph is disjunct from its assertion, just as 
> >english
> >sentences are disjunct from speech acts, we would get a Named Graph
> >representation like this:
> >
> >G1 (ex:Water ex:colour ex:blue)
> >
> >
> >
> >
> >G2 (G1 trix:assertedBy ex:Chris)
> >
> >
> >
> >G3 (G1 trix:denyedBy ex:Patrick.
> >
> >    G1 trix:assertedBy ex:Pat)                               )
> >
> >
> >The graph G1 is independent from the agent. Asserting a graph is a relation
> >between the agent and the graph.
> >It can be done everywhere. The graphs can be moved around, stored in
> >different documents or repositories and whatever.
> 
> Agree with all of the above. Note however that there is no particular 
> reason to believe any such claim of who asserted what, unless it is 
> made by the asserter, which gets us into questions of how to identify 
> the author of such a claim. I am happy to punt on giving an answer to 
> that question, but I'd like us to identify it clearly as one that 
> needs to be answered in order to anchor trust securely.

Just to de-lurk, yes this all makes sense. One technique that I believe 
to be deployable (even if a pragmatic hack) is PGP signing RDF files.
For eg see http://usefulinc.com/foaf/signingFoafFiles

PGP only assures that the file hasn't been changed since the signer 
interacted with it, doesn't assure that the signer asserts it. My 
working guess is that, if the doc itself claims that the signer is its 
creator, that is enough to bootstrap the claim that the signer asserts
the triples encoded in the rdf/xml. Potentially tenuous but I can't
think of how else to roll this stuff out...

Dan

Received on Friday, 12 March 2004 16:08:37 UTC