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Re: Importing RIF documents from RDF - last attempt

From: Ivan Herman <ivan@w3.org>
Date: Fri, 12 Mar 2010 15:34:12 +0100
Message-ID: <4B9A50E4.1050802@w3.org>
To: Chris Welty <cawelty@gmail.com>
CC: Axel Polleres <axel.polleres@deri.org>, RIF <public-rif-wg@w3.org>, Birte Glimm <birte.glimm@comlab.ox.ac.uk>, Chimezie Ogbuji <ogbujic@ccf.org>, Sandro Hawke <sandro@w3.org>
Chris, I understand.

The issue we have is that this statement, if defined somewhere, is
really not SPARQL specific only. Is it o.k. with the RIF group if the
URI used for those predicates are in the RIF namespace somehow?
Alternatively, we can mint a completely separate URI.

Ivan

On 2010-3-12 15:09 , Chris Welty wrote:
> 
> Axel,
> 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.
> 
> -Chris
> 
> 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.
>>
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
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Received on Friday, 12 March 2010 14:33:51 GMT

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