[jira] [Created] (JENA-1496) Inference with SPARQL and GenericRuleReasoner gives different results

["Arhs Team (JIRA)" <ji...@apache.org>]

Arhs Team created JENA-1496:
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             Summary: Inference with SPARQL and GenericRuleReasoner gives different results
                 Key: JENA-1496
                 URL: https://issues.apache.org/jira/browse/JENA-1496
             Project: Apache Jena
          Issue Type: Bug
    Affects Versions: Jena 3.6.0
            Reporter: Arhs Team
         Attachments: DemoApplication.java

Hi,

we are trying to manually infer some properties based on the SKOS definition. Some of our models are huge and cannot be handled by Jena.

We tried OWL reasoner (+micro, +mini) and binding the SKOS definition with bindSchema, we also tried the GenericRuleReasoner with OWL reasoning capabilities but nothing worked. Some inference never finished, was too slow or the memory consumption was too big.

We are now trying to do a lightweight inference of some properties with SPARQL queries or Rules defined in the GenericRuleReasoner (without OWL reasoning). In the rules, we manually create the triples we need : a skos:narrower b -> b skos:broader a, we don't define skos:narrower owl:subPropertyOf skos:broader since we don't have reasoning capabilities enabled.

We tried a few things and we found some inconsistencies between how a model is updated with SPARQL queries and the GenericRuleReasoner if the object is a resource or a literal.

The attached DemoApplication.java gives the following result:

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==== Test adding reasoner inferred object literal - not added
Size model 1, print : 
<http://url.com/one>  <http://www.w3.org/2008/05/skos-xl#literalForm> "http://url.com/two" .
Size inf 2, print : 
<http://url.com/one>  <http://www.w3.org/2008/05/skos-xl#literalForm> "http://url.com/two" .
Add inf to model
Size new model 1, print : 
<http://url.com/one>  <http://www.w3.org/2008/05/skos-xl#literalForm> "http://url.com/two" .
Size deduction model : 1

==== Test adding reasoner inferred object resource - added
Size model 1, print : 
<http://url.com/one>  <http://www.w3.org/2008/05/skos-xl#literalForm> <http://url.com/two> .
Size inf 2, print : 
<http://url.com/two>  a  <http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral> .
<http://url.com/one>  <http://www.w3.org/2008/05/skos-xl#literalForm> <http://url.com/two> .
Add inf to model
Size new model 2, print : 
<http://url.com/one>  <http://www.w3.org/2008/05/skos-xl#literalForm> <http://url.com/two> .
<http://url.com/two>  a  <http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral> .
Size deduction model : 1

==== Test adding sparql inferred object literal - construct model empty
Size model 1
Size construct model 0
Add construct model to model
Size new model 1

==== Test adding sparql inferred object resource - added 
Size model 1
Size construct model 1
Add construct model to model
Size new model 2

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When the object is a resource, a new triple is inferred, visible and can be added to another model for both SPARQL update or GenericRuleReasoner.

When the object is a literal, the SPARQL construct query doesn't return anything, the GenericRuleReasoner infers a triple but it is not visible when printing the model and we cannot add the triple to another model. With the generic rule reasoner, we can still see that there is a triple inferred in the deduction model but we cannot do anything with it.

This is causing some troubles for us because we don't know how to handle that kind of scenarios based on invalid initial query/rule. 

Thank you.

 



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