As well as user-defined rules it is also possible to materialize the built-in standard axioms. Standard axioms are special rules which are used to, for example, derive the subclass transitivity of ObjectLogic or RDF. Often, materializing the standard axioms will significantly improve performance.
Materializing ObjectLogic Standard Axioms
If you want to materialize the ObjectLogic standard axioms you have to turn on the corresponding switch in your OntoConfig.prp. The following standard axioms can be materialized:
|•||Attribute inheritance (Materialize.ObjectLogic.AttributeInheritance)|
|•||Root concepts (Materialize.ObjectLogic.RootConcepts)|
|•||Subclass transitivity (Materialize.ObjectLogic.SubclassTransitivity)|
|•||Subproperty transitivity (Materialize.ObjectLogic.SubpropertyTransitivity)|
|•||Subset relationship for concepts (Materialize.ObjectLogic.SubsetRelationship)|
|•||Subset relationship for properties (Materialize.ObjectLogic.PropertySubsetRelationship)|
|•||Structural inheritance for instances (Materialize.ObjectLogic.StructuralInheritanceForInstances)|
For example, if you want to materialize the subclass transitivity standard axiom you have to put in your OntoConfig
Materialize.ObjectLogic.SubclassTransitivity = on
As a default, no ObjectLogic standard axiom is materialized on startup.
Materializing RDF/S Standard Axioms
When you use the ontology language RDF, you can materialize the RDF standard axioms which are described in the chapter which describes RDF inferending (Inferencing). For example, if you want to materialize the class transitivity then you add the following line to your OntoConfig.prp:
Materialize.RDF.Entailment.ClassTransitivity = on
As a default, no RDF standard axiom is materialized on startup.