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Importing RIF documents from RDF - last attempt

From: Axel Polleres <axel.polleres@deri.org>
Date: Fri, 12 Mar 2010 11:35:11 +0000
Message-Id: <6B9E4B48-AF3D-4CAE-A226-AC1AA8D9113D@deri.org>
Cc: Ivan Herman <ivan@w3.org>, Birte Glimm <birte.glimm@comlab.ox.ac.uk>, Chimezie Ogbuji <ogbujic@ccf.org>, Sandro Hawke <sandro@w3.org>
To: RIF <public-rif-wg@w3.org>
Hi all,

We had the topic of "rif:imports" coming up in SPARQL again in our Entailment regimes taskforce call this week.

The reason why we (from the SPARQL side) would prefer to have that imports mechanism defined in RIF,
is mainly that we think that the URIs to use for defining this imports mechanism should be in  the rif: 
namespace, since this imports mechanism is likely useful not only for SPARQL but also for other
RDF applications that wnat to interact with RIF.

Thus, I wanted to inquire again, whether we'd have a chance to get that an import mechanism for RIF from RDF into
http://www.w3.org/TR/rif-rdf-owl/ ?

If the group overall still thinks that it is too late to get this into the spec, in turn, I wanted to ask/raise 
again how/whether we could proceed to publish this text as a WG Note?

I have earlier made a simple proposal to add a new section to the current spec, which we elaborated a bit now:

1) In the introduction of http://www.w3.org/2005/rules/wiki/SWC,
I would suggest to add:

"RDF Graphs in RIF-RDF-combinations are assumed to not contain any triples using the predicates
rif:imports, rif:ruleset and rif:profile we refer to Section 6 for treatment of such graphs.
"

2) Further, I would suggest to add a new section:
====================================================================================

= 6 Importing RIF rulesets in RDF =

The definitions so far, only covered RIF-RDF-combinations where the RDF graphs did not contain
triples using rif:usingRuleset in predicate positions. To lift this restriction, we define
RIF-X-combinations (R,S) where any of the graphs in S contains triples with the predicates
rif:imports, rif:ruleset and rif:profile
by a reduction to combbinations without such triples as follows.

Let (R, S) be a combination as above. The reduction of R is defined as the
RIF-X-combinations (R', S') where
 (i) S' is identical to S with all rif:imports, rif:ruleset and rif:profile triples removed, 
     and
 (ii) R' is identical to the RIF document R,
      with the addition that R' has additional imports clauses
      Imports( R1 )
      Imports( G P )
     for any triples

       <> rif:imports [rif:ruleset R rif:profile P ].

     in (simple entailed by) S, such that R1 is an IRI referring to a RIF document and
     P is a URI referring to an imports profile as defined in
     Section http://www.w3.org/2005/rules/wiki/SWC#Profiles_of_Imports

Together with the conditions in section 5.2 this ensures that RIF-X-combinations where R is empty, i.e. which
are only defined by a set of RDF graphs, can also import RIF rulesets.

====================================================================================

In case there is a chance to get this on one of the next agendas, please let me know, since I have recently not
really had time to be follow the RIF TCs, but I'd be joining for that.

best,
Axel

P.S.: Condition (i) which removes all the rif:usingruleSet triples, i.e.,
just treats these triples as a directive rather than part of the graph, may be dropped, i.e. simply 
keeping S as is, accepting the rif:imports, rif:ruleset and rif:profile triples as part of the graph.
Received on Friday, 12 March 2010 11:35:46 GMT

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