code: private void rePrimeNF6(AxiomSet as, IConceptMap<IConceptSet> subsumptions) {
          int size = as.getNf6Axioms().size();
          if (size == 0)
              return;
          IConceptSet deltaNF6 = new SparseConceptSet(size);
          for (NF6 nf6 : as.getNf6Axioms()) {
              deltaNF6.add(nf6.getR());
          }
  
          for (IntIterator it = deltaNF6.iterator(); it.hasNext();) {
              int role = it.next();
              for (IntIterator it2 = contextIndex.keyIterator(); it2.hasNext();) {
                  int concept = it2.next();
                  Context ctx = contextIndex.get(concept);
                  if (ctx.getSucc().containsRole(role) && !ctx.getSucc().lookupConcept(role).contains(concept)) {
                      ctx.processExternalEdge(role, concept);
                      affectedContexts.add(ctx);
                      ctx.startTracking();
                      if (ctx.activate()) {
                          todo.add(ctx);
                      }
                  }
              }
          }
      }
docs: These are reflexive role axioms. If an axiom of this kind is added, then
  an "external edge" must be added to all the contexts that contain that
  role and don't contain a successor to themselves.
  
  @param as
  @param subsumptions