Oh, oops. Sorry! XD I guess I figured that the name 'is is so good that something oughta use it. And for some reason, I'm not currently concerned that the name "is" should be restricted to the most picky kind of equality operator (as I was in that thread).
"iso neatly sidesteps them by evoking the precise image of structural equality."
Right now, I don't believe the purpose of 'iso is very precise either. I think a type's designer should extend 'iso with whatever makes intuitive sense for that type, just as long as it's still an equivalence relation. Guess I'm in an informal mood.