code: private boolean isRedundant(IContextMapping<INode> mapping, IMappingElement<INode> e) {
          switch (e.getRelation()) {
              case IMappingElement.LESS_GENERAL: {
                  if (verifyCondition1(mapping, e)) {
                      return true;
                  }
                  break;
              }
              case IMappingElement.MORE_GENERAL: {
                  if (verifyCondition2(mapping, e)) {
                      return true;
                  }
                  break;
              }
              case IMappingElement.DISJOINT: {
                  if (verifyCondition3(mapping, e)) {
                      return true;
                  }
                  break;
              }
              case IMappingElement.EQUIVALENCE: {
                  if (verifyCondition4(mapping, e)) {
                      return true;
                  }
                  break;
              }
              default: {
                  return false;
              }
  
          }// end switch
  
          return false;
      }
docs: Checks the relation between source and target is redundant or not for minimal mapping.
  
  @param mapping a mapping
  @param e       a mapping element
  @return true for redundant relation