public void retrieveSubObjectPropertyAxioms() {
    // this method is to perform a dual operation; it shall retrieve all the declarative object
    // properties categories' annotations,
    // thus filling the objPropCategories Set, while parallelly will, for each category entry
    // retrieve the object properties themselves
    // and adding their entries in the objPropEntries Set.
    Set<OWLSubObjectPropertyOfAxiom> tmpSet;
    OWLObjectPropertyExpression tempDeclarativePropertyClass =
        OWLFactory.getOWLObjectProperty(":DeclarativeProperty", topIxPrefixManager);
    tmpSet =
        topIxOnt.getObjectSubPropertyAxiomsForSuperProperty(
            tempDeclarativePropertyClass); // OWLFactory.getOWLObjectProperty(IRI.create("http://www.semanticweb.org/ontologies/ptyxiaki_v0.6/2011/5/Ontology1308067064597.owl#DeclarativeProperty")));
    Set<OWLSubObjectPropertyOfAxiom> tmpSet2;

    Set<OWLAnnotationAssertionAxiom> tmpAnnSet1;
    Set<OWLAnnotationAssertionAxiom> tmpAnnSet2;
    // to become class variables.

    for (OWLSubObjectPropertyOfAxiom sopAx : tmpSet) {
      String tmpS = sopAx.getSubProperty().toString();
      // categories...
      tmpAnnSet1 =
          topIxOnt.getAnnotationAssertionAxioms(
              IRI.create(
                  tmpS.substring(
                      1, tmpS.indexOf('>')))); // this set only contains one annotation per entry
      for (OWLAnnotationAssertionAxiom aaAx : tmpAnnSet1) {
        String currentObjPropCatName =
            aaAx.getValue().toString().substring(1, aaAx.getValue().toString().indexOf('^') - 1);

        tmpSet2 =
            topIxOnt.getObjectSubPropertyAxiomsForSuperProperty(
                OWLFactory.getOWLObjectProperty(IRI.create(tmpS.substring(1, tmpS.length() - 1))));
        for (OWLSubObjectPropertyOfAxiom sopAx2 : tmpSet2) {
          String tmpS2 = sopAx2.getSubProperty().toString();
          tmpAnnSet2 =
              topIxOnt.getAnnotationAssertionAxioms(
                  IRI.create(tmpS2.substring(1, tmpS2.length() - 1)));

          for (OWLAnnotationAssertionAxiom aaAx2 : tmpAnnSet2) {
            String currentObjPropEntryName =
                aaAx2
                    .getValue()
                    .toString()
                    .substring(1, aaAx2.getValue().toString().indexOf('^') - 1);
            propEntryNameToPropCatName.put(currentObjPropEntryName, currentObjPropCatName);
            propEntryNametoPropEntryIRI.put(
                currentObjPropEntryName, tmpS2.substring(1, tmpS2.length() - 1));
          }
        }
      }
    }
  }
 public void visit(OWLSubObjectPropertyOfAxiom axiom) {
   addChildParent(axiom.getSubProperty(), axiom.getSuperProperty(), axiom);
 }