I have a few questions about reasoning in Jena. Thanks in advance for any answers or suggestions.
As background, here is a simple test case to infer transitive relations between individuals. Protege/Pellet will load this model and infer that A transProp C. <?xml version="1.0"?> <rdf:RDF xmlns="http://www.test.com/test#"; xml:base="http://www.test.com/test"; xmlns:t="http://www.test.com/test#"; xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"; xmlns:owl="http://www.w3.org/2002/07/owl#"; xmlns:xml="http://www.w3.org/XML/1998/namespace"; xmlns:xsd="http://www.w3.org/2001/XMLSchema#"; xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#";> <owl:Ontology rdf:about="http://www.test.com/test"/> <owl:ObjectProperty rdf:about="http://www.test.com/test#simpleProp";> <rdfs:subPropertyOf rdf:resource="http://www.test.com/test#transProp"/> </owl:ObjectProperty> <owl:ObjectProperty rdf:about="http://www.test.com/test#transProp";> <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#TransitiveProperty"/> </owl:ObjectProperty> <owl:NamedIndividual rdf:about="http://www.test.com/test#A";> <simpleProp rdf:resource="http://www.test.com/test#B"/> </owl:NamedIndividual> <owl:NamedIndividual rdf:about="http://www.test.com/test#B";> <simpleProp rdf:resource="http://www.test.com/test#C"/> </owl:NamedIndividual> <owl:NamedIndividual rdf:about="http://www.test.com/test#C"/> </rdf:RDF> Here is a fragment of the code I'm using with Jena 3.1.0. // Preceded by code to set up mySystemInput to read the above. OntModel mySystem = ModelFactory.createOntologyModel( OntModelSpec.OWL_MEM_RULE_INF ); mySystem.read(mySystemInput, null); Model deductionsModel = mySystem.getDeductionsModel(); StmtIterator deducedStatements = deductionsModel.listStatements(); // Followed by code to dump all the statements. The deductionsModel I get does not include the transProp sentences that are inferred by Protege/Pellet. Question: The online page on reasoning suggests that the OWL reasoners that come with Jena might not do all the inferencing that is expected by the OWL standard. On the other hand, an exchange on users@jena a few years ago suggested that inferring transitive properties would/should be done. Is the above reasoner expected to make the inference that Protege/Pellet makes? Question: I also tried using the OWL_MEM_TRANS_INF reasonser. In that case, getDeductionsModel returns null. Is that expected? TODO functionality? Is there a work-around? Question: Should my next step be to integrate Pellet and use that as the reasoner?
