i am proving this statement about strict isotoneness. i will try on my own and you will tell me whether i am okay or not :)
$A$ is subset of $\mathbb{R}$
$f$ is strict isotone $ \Longleftrightarrow \forall x,y\in A (x \neq y \Longrightarrow \frac{f(y)-f(x)}{y-x} > 0)$
i say: if $f$ is strict monotone, then for any x,y with $x
i feel, i amnot showing enough proof here. how to develop the proof technic?
thanks