The post I am replying to made no assumptions about the domain the order is defined on. If it is over the reals, sure, you can use -∞ and ∞. If it is over the integers, you can use MIN_VALUE and MAX_VALUE, sacrificing some of your domain (which might be a problem, depending on the context), or you can use Option[Int], which comes with performance issues.

Or, you can use a range which is a sum of three/four cases, and not worry about any of that.