- From: Jeremy Carroll <jjc@hpl.hp.com>
- Date: Mon, 17 Dec 2007 16:13:37 +0000
- 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) - a POWDER document has a root element, typically wdr:DR, in the POWDER namespace. - 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 b) POWDER documents are constrained by some schema (probably not an XML Schema) so that they roughly follow the pattern given at http://www.w3.org/TR/2007/WD-powder-dr-20070925/#structure or some other similar pattern c) A POWDER processor follows an operational semantics, roughly following the instructions of the various published WDs d) As an RDF/XML document, the formal semantics of a POWDER document is arranged to be true, but weaker than the operational semantics. e) A GRDDL transform is associated with the POWDER namespace f) The GRDDL transform transforms 7 <wdr:ResourceSet> 8 <wdr:includeHosts>example.org</wdr:includeHosts> 9 </wdr:ResourceSet> into 1 <owl:Class> 2 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). g) The formal semantics of the GRDDL result of a POWDER document corresponds closely to the operational semantics of the POWDER document. h) 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. ... Jeremy
Received on Monday, 17 December 2007 16:14:21 UTC