Check of OWL 2 DL profile fails when using language tags

[tobiaswjohn]

I encountered the problem that a valid OWL DL ontology can be classified as not belonging to the profile if language tags are used. The following is a minimal example, defining a single data relation:

Prefix(:=<http://www.example.org/reasonerTester#>)
Ontology(
  Declaration(DataProperty(:dataprop))
  Declaration(NamedIndividual(:a))
  
  DataPropertyAssertion(:dataprop :a "some string"@en)
)

Using the class OWL2DLProfile(), I wrongly get a violation report for the OWL DL profile. The issue seems to be that the object of the data relation is parsed as rdfs:langString in OWLLiteralImplPlain (line 44). However, this type of string is not allowed according to the OWL DL standard.

I am not sure if this is a problem of incorrect parsing or conflicting standards. The RDF standard (3.3; third element) sounds like the parsing is correct.

For reproduction, here is a minimal program that demonstrates the behavior:

OWLOntologyDocumentSource source = new FileDocumentSource(ontFile, new FunctionalSyntaxDocumentFormat());
OWLOntologyManager manager = OWLManager.createOWLOntologyManager();
ont = manager.loadOntologyFromOntologyDocument(source);


OWLProfileReport profileReport = new OWL2DLProfile().checkOntology(ont);
List<OWLProfileViolation> violations = profileReport.getViolations();