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

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)

Dave
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