Re: RDF-ISSUE-79 (undefined-datatype): What is the value of a literal whose datatype IRI is not a datatype? [RDF Concepts]

On Thu, Nov 10, 2011 at 10:45 AM, Richard Cyganiak <richard@cyganiak.de>wrote:

> Antoine,
>
> On 10 Nov 2011, at 14:41, Antoine Zimmermann wrote:
> > This resource can only be known according to a datatype map and only if
> the datatype map contains a pair (http://ex.com/whatever,ddd). Otherwise,
> it is unknown.
>
> Can you confirm that this is really an “if and only if”?
>
> Is it somehow possible under RDFS-Entailment + D-Entailment to get a value
> for "foo"^^bar if bar is not in the datatype map?
>
> > The text should rather say something like:
> >
> > "If <x,ddd> is not in the datatype map then a typed literal with
> datatype IRI x is interpreted as an unknown resource."
>
> Would it be correct to say the following:
> “The value of a literal whose datatype IRI is not in the datatype map is
> unknown.”
>

That's almost exactly what RDF Semantics 2004 says: "Typed literals whose
type is not in the datatype map of the interpretation are treated as
before, i.e. as denoting some unknown thing." (Section 5.1)

I would prefer to have literals of type rdf:LangString denote themselves in
all interpretations rather than some unknown thing, but I don't know how
best to make it happen.  Clearly it can't be done through the L2V mechanism.

-Alex