code: private static boolean invalidMembershipProperty(final Triple triple) {
          return (LDP.hasMemberRelation.equals(triple.getPredicate())
                          || LDP.isMemberOfRelation.equals(triple.getPredicate()))
                          && restrictedMemberProperties.contains(triple.getObject());
      }
docs: is not equal to ldp:contains or any of the other cardinality-restricted IRIs