>> Actually, every iterator (singular, initialized, pointing to viable
>> memory or not) defines its own empty range.
>
> No, I don't believe that's quite correct.  There are lots of things one
> can do with iterators in a range that one cannot do with a
> minimally-singular iterator.

Well, two anyways: == and !=. Given that the standard doesn't allow
those on singular-valued iterators, you're right. I think the standard
is a little too strict, here.