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

Le 10/11/2011 16:45, Richard Cyganiak a écrit :
> 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 (,ddd). Otherwise, it is unknown.
> Can you confirm that this is really an “if and only if”?

I confirm. The interpretation of a typed literal is a resource (any 
resource) in simple entailment. RDF and RDFS constrain this by imposing 
a specific interpretation on rdf:XMLLiteral only (so all other typed 
literals are interpreted as any resource). In D-entailment, all typed 
literals are again any kind of resources EXCEPT if they are in the 
datatype map. You can quickly check this by looking at the HTML tables 
of RDF Semantics (check the tables with these captions):

"Definition of a simple interpretation."
"Semantic conditions for ground graphs."
"Semantic conditions for blank nodes."
"RDF semantic conditions."
"RDF axiomatic triples."
"RDFS semantic conditions."
"RDFS axiomatic triples."
"General semantic conditions for datatypes."

> Is it somehow possible under RDFS-Entailment + D-Entailment to get a value for "foo"^^bar if bar is not in the datatype map?

It is not possible. The value is only defined for datatypes that are in 
the map (which is application dependent).

>> 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.”

Yes, I think this works too.

> Best,
> Richard

Antoine Zimmermann
ISCOD / LSTI - Institut Henri Fayol
École Nationale Supérieure des Mines de Saint-Étienne
158 cours Fauriel
42023 Saint-Étienne Cedex 2
Tél:+33(0)4 77 42 66 03
Fax:+33(0)4 77 42 66 66

Received on Monday, 14 November 2011 15:09:19 UTC