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Re: [TF-ENT] Querying datasets with default plus named graphs

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Thu, 8 Oct 2009 14:38:12 +0100
Message-ID: <492f2b0b0910080638s18874d06g92b579e1b9e91193@mail.gmail.com>
To: Axel Polleres <axel.polleres@deri.org>
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>, Ivan Herman <ivan@w3.org>, Andy Seaborne <andy.seaborne@hp.com>
2009/10/8 Axel Polleres <axel.polleres@deri.org>:
> p.s.: the proper URL for the references should have been:
>
> 1. http://www.w3.org/TR/rif-rdf-owl/#Importing_RDF_and_OWL_in_RIF
>
> Also, FWIW, RIF has already defined some URIs for entailment regimes, we may
> think about adopting those,
> cf.  http://www.w3.org/TR/rif-rdf-owl/#Specific_Profiles

Hm, I am not sure I would like IRIs with rif-import-profile for SPARQL
entailment regimes.
http://www.w3.org/2007/rif-import-profile#RDFS
Ordo you mean to just use the names such as RDFS, Simple, OWL-DL?
That's fine for me.
Birte

> best,
> Axel
>
> On 8 Oct 2009, at 14:05, Axel Polleres wrote:
>
>>> > It also raises an issue on the RIF side. RIF rules cannot be expressed
>>> > in
>>> > RDF. How would one add RIF rules to an entailement regime if we wanted
>>> > to
>>> > cover RIF? It might be a showstopper for that case:-(
>>>
>>> In my total RIF naivity, I would assume you can say:
>>>
>>> SELECT ?o FROM <http://example.org/myrules.rif> WHERE { :s :p ?o . }
>>>
>>
>> I was thinking that one viable alternative would be viewing RIF rulesets
>> rather at the
>> level of *defining* an entailment regimes in their own right,
>> thus having them more at the level of service descriptions...
>>
>> So, one could define say in SD
>>
>>  myEndpoint sd:EntailmentRegime sd:rdfs .
>>
>>  myEndpoint sd:EntailmentRegime sd:owl .
>>
>> or, alternatively:
>>
>>   myEndpoint sd:EntailmentRegime
>> <http://example.org/myCustomEntailmentRules.rif>
>>
>> where <http://example.org/myCustomEntailmentRules.rif> points to a RIF
>> ruleset, describing the supported entailment rules.
>>
>> Alternatively, we could also allow to use
>>
>> owl:imports to refer to RIF rulesets (just as RIF allows in its own
>> imports directive to refer to OWL ontologies, cf. [1]
>>
>> Axel
>>
>> 1. http://www.w3.org/2005/rules/wiki/SWC#Importing_RDF_and_OWL_in_RIF
>>
>>
>> On 8 Oct 2009, at 11:34, Birte Glimm wrote:
>>
>>> 2009/10/8 Ivan Herman <ivan@w3.org>:
>>> >
>>> > Axel Polleres wrote:
>>> [snip]
>>> >> +1 to keep entailments local to the separate  graphs in the DS
>>> >> (<chairhatoff> although  I  personally consider it a drawback that you
>>> >> can't refer to ontologies from named graphs)
>>> >
>>> > Hm. Yes, this seems to be a consequence which is a bit disagreeable
>>> > indeed:-(
>>> >
>>> > In OWL, I can of course use owl:import in my WHERE clause (Birte, this
>>> > is
>>> > all right, isn't it?) which is not that bad, the user has to make
>>> > things
>>> > explicit. But this does not help the RDFS case.
>>>
>>> In OWL you can use imports, but I suppose you mean FROM and not WHERE
>>> clause. If the ontology you are querying (as given in the FROM (NAMED)
>>> clause) contains imports, then all imports will be loaded and the
>>> axioms from the imported ontologies will be taken into account for
>>> finding the query answers.
>>>
>>> > It also raises an issue on the RIF side. RIF rules cannot be expressed
>>> > in
>>> > RDF. How would one add RIF rules to an entailement regime if we wanted
>>> > to
>>> > cover RIF? It might be a showstopper for that case:-(
>>>
>>> In my total RIF naivity, I would assume you can say:
>>>
>>> SELECT ?o FROM <http://example.org/myrules.rif> WHERE { :s :p ?o . }
>>>
>>> Here I assume that myrules.rif contains the rules and references
>>> (imports) for the relevant RDF graphs. In the RIF OWL compatibility
>>> doc it says:
>>>
>>> A RIF document that refers to (imports) RDF graphs and/or RDFS/OWL
>>> ontologies, or any use of a RIF document with RDF graphs, is viewed as
>>> a combination of a document and a number of graphs and ontologies.
>>> This document specifies how, in such a combination, the document and
>>> the graphs and ontologies interoperate in a technical sense, i.e., the
>>> conditions under which the combination is satisfiable (i.e.,
>>> consistent), as well as the entailments (i.e., logical consequences)
>>> of the combination. The interaction between RIF and RDF/OWL is
>>> realized by connecting the model theory of RIF [RIF-BLD] with the
>>> model theories of RDF [RDF-Semantics] and OWL [OWL2-Semantics],
>>> respectively.
>>>
>>> In my example, I assume that myrules.rif is such a document as
>>> mentioned above and you would query the RDF graphs pls the entailmens
>>> that you get from the rules.
>>>
>>> Birte
>>>
>>> > Ivan
>>> >
>>> >
>>> > --
>>> >
>>> > Ivan Herman, W3C Semantic Web Activity Lead
>>> > Home: http://www.w3.org/People/Ivan/
>>> > mobile: +31-641044153
>>> > PGP Key: http://www.ivan-herman.net/pgpkey.html
>>> > FOAF: http://www.ivan-herman.net/foaf.rdf
>>> >
>>>
>>>
>>>
>>> --
>>> Dr. Birte Glimm, Room 306
>>> Computing Laboratory
>>> Parks Road
>>> Oxford
>>> OX1 3QD
>>> United Kingdom
>>> +44 (0)1865 283529
>>>
>>
>
>



-- 
Dr. Birte Glimm, Room 306
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283529
Received on Thursday, 8 October 2009 13:38:46 GMT

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