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POWDER: my rabbit

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Mon, 17 Dec 2007 16:13:37 +0000
Message-ID: <4766A031.6050109@hpl.hp.com>
To: Phil Archer <parcher@icra.org>
CC: www-archive@w3.org, "Carroll, Jeremy John" <jeremy.carroll@hp.com>, Dan Brickley <danbri@danbri.org>, "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>, Ivan Herman <ivan@w3.org>, Bijan Parsia <bparsia@cs.man.ac.uk>

Attempting to pull something from my hat ....

How about:


- a POWDER document has a root element, typically wdr:DR, in the POWDER 

- a POWDER document is an RDF/XML document

- an RDF/XML document that uses POWDER vocabulary but does not have a 
root element in the POWDER namespace is not a POWDER document


POWDER documents are constrained by some schema (probably not an XML 
Schema) so that they roughly follow the pattern given at


or some other similar pattern


A POWDER processor follows an operational semantics, roughly following 
the instructions of the various published WDs


As an RDF/XML document, the formal semantics of a POWDER document is 
arranged to be true, but weaker than the operational semantics.

A GRDDL transform is associated with the POWDER namespace

The GRDDL transform transforms

7      <wdr:ResourceSet>
8        <wdr:includeHosts>example.org</wdr:includeHosts>
9      </wdr:ResourceSet>


1  <owl:Class>
3    <owl:equivalentClass>
4      <owl:Restriction>
5        <owl:onProperty rdf:resource="&powder;#includeHost" />
6        <owl:hasValue>example.org</owl:hasValue>
7      </owl:Restriction>
8    </owl:equivalentClass>
9  </owl:Class>

etc. (i.e. the GRDDL transform embeds expert knowledge of OWL).

The formal semantics of the GRDDL result of a POWDER document 
corresponds closely to the operational semantics of the POWDER document.

The formal semantics of a POWDER document read by a non-GRDDL aware, 
non-POWDER aware, RDF processor is a proper consequence of the formal 
semantics of a POWDER aware and GRDDL aware reading of the same document.


That seems to hit enough of the targets.

Some obvious drawbacks

It continues an overly technocractic semantic web
where there is a two-tier (or even three tier) system of formalism, with 
the 'true' definitions being defined on the 'highest' plane, that is 
accessibly only to an elite with a particular type of 
mathematical/logical background.

There continues to be a divorce between an operational practice, that is 
probably defined in terms of POWDER as XML documents, and actually 
implemented using SAX and DOM like interfaces, and a theoretical model, 
built on semantic web recommendations.


Received on Monday, 17 December 2007 16:14:21 UTC

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