W3C home > Mailing lists > Public > www-rdf-logic@w3.org > June 2002

Re: Implementing statement grouping, contexts, quads and scopes

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Thu, 27 Jun 2002 15:44:54 +0300
To: ext Jonathan Borden <jonathan@openhealth.org>, Danny Ayers <danny666@virgilio.it>, RDF Logic <www-rdf-logic@w3.org>
Message-ID: <B940E376.177EE%patrick.stickler@nokia.com>

On 2002-06-27 14:39, "ext Jonathan Borden" <jonathan@openhealth.org> wrote:

> Danny Ayers wrote:
>> So essentially I'm suggesting two aspects to the context/grouping issue,
>> firstly that in the wild (on the web or otherwise available through public
>> interfaces) the triples exist implicitly as quads, i.e.
>> [email:765] [urn:Sassi] [a:hasSpecies] [a:cat]
>> and that whether or not triples get asserted remains entirely a local
> issue,
>> decided by the implementation.
>> Putting this more strongly, we only really have two contexts - 'in the
> wild'
>> and 'in application X'.
> Whether triples get asserted is not entirely a local issue, nor should it
> be.
> Consider above, that your triples are "colored" by the base URI of their
> containing document, in this case your e-mail. Now consider a "current
> document" which is identified (as always) by a URI.
> In base RDF, a triple is _asserted_ when its color (i.e. base URI) is equal
> to the "current document" URI. Now how one determines the "current document"
> is outside the scope of RDF, and needs to be more formally addressed for a
> semantic web to get working.

This is similar to how I have been thinking about statement qualification.

Rather than quads, simply have qualified reified statements (statings)
with arbitrary properties: source, scope, authority, layer (e.g. OWL)
etc. and the 'live' knowledge base then simply becomes a dynamic view
into the sandbox by defining selection criteria for reified statements
based on any number of qualifications.

Thus, one can "virtually assert" statements from multiple sources,
authorities, scopes, etc in any combination. And inferred statements
could be expressed as reified statements with a session specific
scope qualification, which treats them as asserted for that session
and also allows those statements to be conveniently purged
later when no longer needed. This is useful e.g. in a mobile context
where clients may enter a context, make queries and requests from
local servers which require inference, and then leave that context
and thus the knowledge about the client and the clients inquiries
are transient and should not be saved persistently.



Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Thursday, 27 June 2002 08:40:22 UTC

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