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Re: not the negative guards alone cause pathologic examples!!!!...

From: Axel Polleres <axel.polleres@deri.org>
Date: Sat, 27 Sep 2008 17:16:34 -0400
Message-ID: <48DEA2B2.40708@deri.org>
To: Axel Polleres <axel.polleres@deri.org>
CC: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

Axel Polleres wrote:
> Ooops, forget it, the examples was nonsense... seems that the jetlag 
> kicks in. but I am still not entirely convinced that only negative 
> guards are the problem.
> 
> axel

sorry, sorry, rethought it. indeed only the negative guards are the 
preds defined in terms of failure of another predicate, so indeed they 
are the only problematic ...

> Axel Polleres wrote:
>> Please note that Jos pathological use case
>>
>> http://www.w3.org/2005/rules/wiki/Disjunctive_Information
>>
>> can very similarly be modeled with comparison operators, which doesn't 
>> only put negative guards, but also our "convenient"
>> less-than-or-equal, greater-than-or-equal predicates at risk:
>>
>>
>> Document(
>> Prefix(ex http://example.com/example#)
>> Prefix(pred http://www.w3.org/2007/rif-builtin-predicate#)
>>
>> Group(
>> ex:p(ex:a)
>> Forall ?x (1=2 :- And (ex:p(?x) pred:less-than(?x 5)
>> pred:greater-than(?x 0) ) )
>> )
>>
>> entails:
>>
>> Or ( pred:greater-than-or-equal(ex:a 5)
>>      pred:less-than-or-equal(ex:a 0) )
>>
>>
>> best,
>> Axel
>>
>>
> 
> 


-- 
Dr. Axel Polleres, Digital Enterprise Research Institute (DERI)
email: axel.polleres@deri.org  url: http://www.polleres.net/

Everything is possible:
rdfs:subClassOf rdfs:subPropertyOf rdfs:Resource.
rdfs:subClassOf rdfs:subPropertyOf rdfs:subPropertyOf.
rdf:type rdfs:subPropertyOf rdfs:subClassOf.
rdfs:subClassOf rdf:type owl:SymmetricProperty.
Received on Saturday, 27 September 2008 21:17:18 GMT

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