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Re: ISSUE-61 (IRI-Casts): Casting to/from rif:iri [DTB]

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Tue, 10 Jun 2008 13:15:59 -0400
To: Jos de Bruijn <debruijn@inf.unibz.it>
Cc: Rule Interchange Format Working Group WG <public-rif-wg@w3.org>
Message-ID: <20080610131559.2d41c0a9@cs.sunysb.edu>

This makes iriToString a multivalued function (i.e., the same iri has several
string interpretations). Is this what we want?


	--michael  

On Tue, 10 Jun 2008 16:40:04 +0200
Jos de Bruijn <debruijn@inf.unibz.it> wrote:

> 
> See [1] and preceding the messages in the thread for a description of 
> the semantic problems.  In [1] I also proposed a casting predicate that 
> seems to work.
> 
> In summary, the biggest semantic challenge in casting IRIs to strings is 
> that several different IRIs may be mapped to the same string.  The 
> following was my proposal:
> 
> "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.
> 
> I think this predicates should be sufficient for most of the use cases.
> 
> 
> Best, Jos
> 
> Rule Interchange Format Working Group Issue Tracker wrote:
> > 
> > ISSUE-61 (IRI-Casts): Casting to/from rif:iri [DTB]
> > 
> > http://www.w3.org/2005/rules/wg/track/issues/
> > 
> > Raised by: Christopher Welty
> > On product: DTB
> > 
> > It is clear users of RIF dialects such as BLD will want to be able to convert (cast) instances of rif:iri to/from other datatypes, in particular strings and possibly rif:text.
> > 
> > In general, a casting mechanism is not present in DTB and should be added.
> > 
> > 
> > 
> 
Received on Tuesday, 10 June 2008 17:16:56 GMT

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