Is there any notation for $\max_x f(x)-\min_x f(x)$?
It's the range or the variation of the function. But range usually refers to the set, where variation usually refers to the arc . What I want is that I can write
$$x f(g(x)) = \max_x f(g(x))-\min_x f(g(x))$$
in order to simplify the notation.
I don't want to define a new notation if there is a common one. If there's none, what is a good name for it?