Question 142
Does there a function $f: \mathbb{R} \rightarrow \mathbb{R}$ exist, that for any real numbers $x$, $y$ the following inequality is fulfilled:
$$
f(x - f(y)) \le x - y f(x)?
$$
$$
f(x - f(y)) \le x - y f(x)?
$$
MathNet 2016-part-06 — 184 problems (EN–VI) Question 142
Math Olympiad Vault · MathNet 2016-part-06 — 184 problems (EN–VI)