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Re: [UCR] ISSUE-12 and ACTION6198 (semantic web rule language) - and also the SPARQL topic

From: Axel Polleres <axel.polleres@urjc.es>
Date: Tue, 09 Jan 2007 23:05:33 +0100
Message-ID: <45A411AD.3040209@urjc.es>
To: Sandro Hawke <sandro@w3.org>
CC: Dave Reynolds <der@hplb.hpl.hp.com>, Christian de Sainte Marie <csma@ilog.fr>, RIF WG <public-rif-wg@w3.org>

Just one question, if we
a) can show that SPARQL itself maps to a RIF dialect (which allows to 
access RDF and OWL data) and calls of built-in functions like CXpath 
functions etc. and

b) view SPARQLs CONSTRUCT queries as well as nothing else than a rule 
dialect (at least the expressivity of SWRL, i.e. HORN over RDF/OWL atoms 
is for sure covered with such construct queries)

then we solve both issues: the one of a semantic Web rules language
(just using SPARQL CONSTRUCT as its syntax and interchange with other 
rules on top of RDF enabled via its RIF version) and the one how to 
integrate SPARQL queries in conditions semantically (one could still 
view it as a blackbox as well, of course, but SPARQL queries would be 
equally definable as part of an extended rule set.)

I have made an attempt on this which I also posted to this list some 
time before Christmas, see :
http://lists.w3.org/Archives/Public/public-rif-wg/2006Dec/0002

(the translation from SPARL to rules defined there is not limited to the 
proposed Prolog style language)

If you think this approach is too naive, let me know, but at least it 
seems an obvious one.

Sorry that I had to miss the teleconf today, doctor's appointment, 
unfortunately I also have to miss next time due to travelling, but I 
would be looking forward to further discuss this possibility.

best,
axel

Sandro Hawke wrote:
>>Sandro Hawke wrote:
>>>csma:
>>>
>>>>>>PROPOSED - The RIF WG will define a small number of standard dialects. 
>>>>>>Although the design goal of each dialect will be rule interchange, any
>>>>>>or all of these dialects may be considered standard semantic web rule 
>>>>>>languages.
>>>
>>>dave in http://lists.w3.org/Archives/Public/public-rif-wg/2007Jan/0012
>>>
>>>>>PROPOSED - The RIF WG will define a small number of standard dialects.
>>>>>Although the design goal of each dialect will be rule interchange, each 
>>>>>may be considered a rule language. Since RIF will support rules which 
>>>>>can process RDF as data and will be compatible with OWL then any or all 
>>>>>of these dialects could form the basis of some future standard semantic 
>>>>>web rule languages. However, the RIF WG is not committed to developing 
>>>>>any such proposals nor laying any particular foundations for them beyond 
>>>>>the compatibility requirements mandated by the charter.
>>>
>>>csma:
>>>
>>>>PROPOSED - The RIF WG will define a small number of standard dialects.
>>>>Although each dialect may be considered a rule language, it will be 
>>>>designed for the sole purpose of rule interchange. Since RIF will 
>>>>support rules that can process RDF as data and will be compatible with 
>>>>OWL then any or all of these dialects could form the basis of some 
>>>>future standard semantic web rule languages. However, the RIF WG is not 
>>>>committed to developing any such proposals nor laying any particular 
>>>>foundations for them beyond the compatibility requirements mandated by 
>>>>the charter.
>>
>>I'm happy with this modified proposal.
>>
>>
>>>I'm still not comfortable with the "basis" hedge.  I am comfortable
>>>calling each dialect a Semantic Web rule language.  There have been
>>>debates about whether "the standard SWRL" should be in each of several
>>>styles [1] -- split along the same lines as the incompatible dialects.
>>>So, using Christian's latest version, I suggest:
>>>
>>>----------------------------------------
>>>PROPOSED - The RIF WG will define a small number of standard dialects.
>>>Although each dialect may be considered a rule language, it will be
>>>designed for the sole purpose of rule interchange.  Since RIF will
>>>support rules that can process RDF as data and will be compatible with
>>>OWL then each these dialects will function as a different type of
>>>Semantic Web rule language.  The Working Group does not anticipate
>>>labeling one or more dialects as the "standard" one for the Semantic
>>>Web unless clear feedback emerges to motivate such a labeling.
>>>----------------------------------------
>>
>>I'm less happy with this one but I guess I could live with it.
>>
>>I don't like the claim that all RIF dialects are semantic web rule 
>>languages. Apart from whether they have useful sets of relevant builtins 
>>(see separate discussion) I don't think all RIF dialects are going to be 
>>equal in terms of OWL and RDFS compatibility. For example, a dialect 
>>with an object style slotted syntax with closed signatures would not be 
>>a good one to pick IMHO. There is nothing *stopping* anyone using such a 
>>dialect with RDF data but I'd rather not give it explicit working group 
>>endorsement without a lot of thought.
>>
>>This phrasing suggests that all that would be left would be rubber 
>>stamping some subset of the dialects as "standard". In fact, if there 
>>ever is a working group set up to propose a set of standard semantic web 
>>rule languages I think it would want to do design work on dialects that 
>>fit in well with the existing semweb stack which may not match the 
>>dialects we'll end up with; then there's the work on a usable syntax, 
>>appropriate libraries of builtins etc.
> 
> 
> Let's try a smaller change from Christian's then:
> 
> ---------------------------------
> PROPOSED - The RIF WG will define a small number of standard dialects.
> Although each dialect may be considered a rule language, it will be
> designed for the sole purpose of rule interchange.  Since RIF will
> support rules that can process RDF as data and will be compatible with
> OWL then any or all of these dialects might be usable as a Semantic Web
> rule language.  The Working Group does not anticipate labeling any of
> these dialects as "standard" for the Semantic Web.
> ---------------------------------
> 
> How's that?
> 
>     -- Sandro
> 
> 
> 
> 
> 


-- 
Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/
Received on Tuesday, 9 January 2007 22:09:18 GMT

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