RIF must cover RDF triples as data

[Resend due to list email problems. Apologies if this is a duplicate.]

On Sept 12th Chris asked for a volunteer to draft an expansion of phase 
1 requirement "RDF Data". The notion, I think, is that RDF and OWL 
compatibility have special mention in the RIF charter and so deserve a 
fuller explanation of what we regard as in-scope for phase 1. [*]

I've not had time to think about this properly (which is why I didn't 
volunteer) but here's a "toe in the water" suggestion to at least try to 
understand what sort of thing is required.

[[[
*RDF Data*

RIF must cover RDF triples as data where compatible with Phase 1 semantics.

Specifically:

o RIF MUST provide a mapping from bNode-free RDF statements to RIF facts 
so that RIF rules can be applied to (data derived from) RDF fact bases. 
This MAY be a "natural" mapping in the sense that RDF facts are mapped 
to ground instances of unary and binary RIF predicates or MAY be based 
on a "holds" predicate.

This mapping will support the derivation of new RDF statements (i.e. 
bNode-free RDF statements can be made in the head of rules).

Note that this RDF mapping will not imply any assumed implementation of 
RDF-D-entailment or RDFS semantics, just RDF conjunctive assertion of 
ground facts. There will be no assumed axiom base (in particular, no 
assumed infinite axiom base of rdfs:ContainerMembership properties). 
Applications wishing to employ RDFS semantics would need to include 
appropriate RDFS axioms and closure rules explicitly.

o RIF MAY extend this mapping to include RDF statements involving 
bNodes. At this point the working group reserves the right to defer 
bNode handling to phase 2, to limit bNode usage to rule bodies only or 
to approximate bNode semantics though the use of skolem constants.

o RIF MAY define an external predicate that will enable RIF rulesets to 
query web-based SPARQL datasources.
]]]

Is this the *type* of thing that people have in mind?

If so, how close are the details? For example, should the SPARQL one be 
a MUST?

Dave

[*] This probably also relates to issue 12 but there is a separate, 
rather quiet, email thread on that:
http://lists.w3.org/Archives/Public/public-rif-wg/2006Sep/0024.html

Received on Monday, 25 September 2006 20:28:59 UTC