Question 184
Find all functions $f: \mathbb{R}^+ \to \mathbb{R}^+$, that satisfy the inequalities
(i) $f(x + y) \geq f(x) + y$
(ii) $f(f(x)) \leq x$
for all positive $x$ and $y$.
(i) $f(x + y) \geq f(x) + y$
(ii) $f(f(x)) \leq x$
for all positive $x$ and $y$.