public boolean isSubRelation(RelationType other) {
    if (other == this) return true;
    return switch (this) {
      case LE -> other == LT || other == EQ;
      case GE -> other == GT || other == EQ;
      case NE -> other == LT || other == GT;
      default -> false;
    };
  }
public boolean isSubRelation(RelationType other)