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Re: Importing RIF documents from RDF - last attempt

From: Chris Welty <cawelty@gmail.com>
Date: Fri, 12 Mar 2010 09:09:05 -0500
Message-ID: <4B9A4B01.8070704@gmail.com>
To: Axel Polleres <axel.polleres@deri.org>
CC: RIF <public-rif-wg@w3.org>, Ivan Herman <ivan@w3.org>, Birte Glimm <birte.glimm@comlab.ox.ac.uk>, Chimezie Ogbuji <ogbujic@ccf.org>, Sandro Hawke <sandro@w3.org>


I really really really do not understand why it matters whether RIF specifies this or SPARQL. 

RIF should be viewed as read-only right now unless there is an error.


Axel Polleres wrote:
> 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.

Dr. Christopher A. Welty                    IBM Watson Research Center
+1.914.784.7055                             19 Skyline Dr.
cawelty@gmail.com                           Hawthorne, NY 10532
Received on Friday, 12 March 2010 14:09:45 UTC

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