right, right.  that makes sense.  even poking around the net a bit, i can see how you can't determine min or max without knowing something about the equation in the first place.  it was less that i was expecting magic than i feel like i don't properly understand some of the different types of Math nodes.  that is, i understand them sort of literally, but not in a more flexible,intuitive way.  well, and while i can follow explanations when you give them, the actual inventing process where you go from what you want to an equation to specific nodes, is completely opaque to me.  so i have much less idea of what is possible and what isn't than i should. 

i really appreciate you taking the time to write about all this.  i know you have lots of other stuff to do.