Re: [Fwd: Re: [DTB] Datatypes and Built-ins first run to clean up and extend the initial list]

Dave Reynolds wrote:
> 
> Jos de Bruijn wrote:
> 
>> So, we really want to take into account all IRIs representing a 
>> particular domain element.  Since this is a set, we would need to use 
>> a built-in predicates.  For example:
>>
>> "Let I be an interpretation, let u be an element in the domain of I, and
>> let {i1, ..., in} be the set of IRIs that denote u, i.e. for each ij 
>> (1 <= j <= n) IC(ij)=u.  IR(iriToString)(u,"ij")=t for (1 <= j <= n); 
>> IR(iriToString)(u,s)=f for every element s not in {"i1", ..., "in"}."
>>
>> The rule set
>> iriToString("b"^^rif:iri,"b"^^xsd:string)
>>
>> is satisfied in every RIF interpretation.
> 
> But in any semantic web context  one couldn't determine the truth or 
> falsity of:
> 
>  iriToString("foo"^^rif:iri,"bar"^^xsd:string)

right.  In some interpretations the formula might be true, whereas in 
other interpretations it would be false.  So, it would not be entailed 
by the empty rule set.

Best, Jos

> 
> Dave

-- 
                          debruijn@inf.unibz.it

Jos de Bruijn,        http://www.debruijn.net/
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