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Re: Importing RDF documents from RIF - part 2

From: Jos de Bruijn <debruijn@inf.unibz.it>
Date: Tue, 19 Jan 2010 16:07:14 +0100
Message-ID: <4B55CAA2.5050006@inf.unibz.it>
To: Axel Polleres <axel.polleres@deri.org>
CC: public-rif-wg@w3.org
This sounds like a reasonable extension of the RDF semantics. Not
convinced, though, that this is in the scope of the RIF-RDF+OWL spec.
For this reason, and for procedural reasons, I suggest that if such an
extension of RDF is of wider interest, a separate spec be written for
this extension.

Furthermore, I am not convinced that extending RDF is the best solution
to your problem of querying RIF-RDF combinations using SPARQL: RIF is
"on top of" RDF. I think it would be better to refer to the RIF ruleset
from the SPARQL query, and have the RIF ruleset import the RDF dataset.

By the way, I would be very interested in the semantics you have in mind
for the SPARQL queries on RIF ruleset.


Cheers, Jos

On 2010-01-19 15:55, Axel Polleres wrote:
> Here the easy-to-digest version:
> 
> In order to enable the import of RIF documents from RDF, I suggest the addition of a new section 
> 6 (or alternatively a new subsection to section 5) to 
> http://www.w3.org/2005/rules/wiki/SWC#Semantics_of_RIF-RDF_Combinations
> which essentially says the following:
> 
> ====================================================================================
> 
> = 6 Importing RIF rulesets in RDF =
> 
> The models of a RIF-X-combination (R,S) where any of the graphs in S contains a ground triple
> 
>    R1 rif:usedWithProfile P .
> 
> such 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
> are restricted to those models which are also models of (G, R') where R' is identical to the RIF document R, 
> with the addition that R' has additional imports clauses
> 
>   Imports( R1 )
>   Imports( G P )
> 
> 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.
> 
> ====================================================================================
> 
> I think this should work apart from that there is one small issue which I consider possibly "suboptimal" 
> as opposed to "owl:imports".
> 
> The triple 
>    R1 rif:usedWithProfile P .
> is in such case still be considered part of the "data" whereas owl:imports triples are in fact not considered in the OWL direct semantics, right?
> 
> maybe those better filled in about "owl:imports" can help, I could actually also try to solicit help/alternative suggestions from people that
> have a more complete understanding on that matter.
> 
> best,
> Axel

-- 
Jos de Bruijn
  Web:   http://www.debruijn.net/
  Phone: +39 0471 016224
  Fax:   +39 0471 016009
Received on Tuesday, 19 January 2010 15:07:50 GMT

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