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Re: ACTION-733 started: my very belated OWLRL-RIF review

From: Axel Polleres <axel.polleres@deri.org>
Date: Fri, 19 Feb 2010 14:50:54 +0000
Message-Id: <787CC1F6-4C52-4AFC-AABF-369B99B76F67@deri.org>
To: Dave Reynolds <der@hplb.hpl.hp.com>, RIF <public-rif-wg@w3.org>
p.s.: Likewise this applies to the rule templates for allDiscjointClasses and allDisjointProperties

Axel

On 19 Feb 2010, at 14:46, Axel Polleres wrote:

> Hi all,
> 
> I just realise that my formerly proposed correction for (* eq-diff2 *) also needs to be carried over to the appendix of
> http://www.w3.org/2005/rules/wiki/OWLRL
> 
> cf. http://www.w3.org/2005/rules/wiki/OWLRL#Appendix:_OWL_2_RL_to_RIF_translation
> 
> the template rule for 
> 
> (?a rdf:type owl:AllDifferent)
> (?a owl:members ?l)
> 
> in Section 7.2 templateRules algorithm has the same problem that and needs to be changed likewise!
> 
> cheers,
> Axel
> 
> On 15 Sep 2009, at 09:34, Axel Polleres wrote:
> 
>> Sorry, I had completely delayed this... here my first few comments (upto end of section 4.3), the rest to follow shortly...
>> 
>> 
>> 
>> 1)
>> the suggestion of rif:error as a unary predicate is a good idea, but conflicts with the use of rif:error as a 0-ary prediacte in the RDF-OWL-compatibility document [1]
>> 
>> 2)
>> I am afraid there is a problem with rule (* eq-diff2 *)... It does not prevent that ?x and ?y bind to the SAME member of the list, where no inconsitency should apply... the solution is to extend the memeber predicate with an index. and let the rule apply to differently indexed members only, i.e. :
>> 
>> 
>> Group (
>>  Forall ?list ?hd (
>>    _member(?list ?hd 0 ) :- ?list[rdf:first -> ?hd] )
>> 
>>  Forall ?list ?tl ?x (
>>    _member( ?list ?x External( func:numeric-add( ?i+1 ) ) ) :- And( ?list[rdf:rest -> ?tl] _member(?tl ?x ?i) ) )
>> )
>> 
>> then (* eq-diff2 *) can be rewritten to:
>> 
>>  Forall ?x ?y ?l (
>>   rif:error("AllDifferent") :- And (
>>       ?l[rdf:type -> owl:AllDifferent]
>>       _member(?l ?x ?i) _member(?l ?y ?j)
>>       External( pred:numeric-not-equal ( ?i ?j ) )
>>       ?x[owl:sameAs->?y] ) )
>> 
>> And analogously for   (* prp-adp *) and (* cax-adc *)
>> 
>> 
>> 
>> 3)
>> Haskey --> HasKey
>> 
>> 
>> 
>> 
>> 
>> 
>> 1. http://www.w3.org/TR/rif-rdf-owl/#Appendix:_Embeddings_.28Informative.29
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> -- 
>> Dr. Axel Polleres
>> Digital Enterprise Research Institute, National University of Ireland, Galway
>> email: axel.polleres@deri.org  url: http://www.polleres.net/
>> 
>> 
>> 
> 
Received on Friday, 19 February 2010 14:51:28 GMT

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