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