Question 156
Find all functions $f: \mathbb{R} \rightarrow \mathbb{R}$ satisfying the conditions:
1. $f(x+1) \geq f(x)+1$ for all $x \in \mathbb{R}$;
2. $f(x y) \geq f(x) f(y)$ for all $x, y \in \mathbb{R}$.
1. $f(x+1) \geq f(x)+1$ for all $x \in \mathbb{R}$;
2. $f(x y) \geq f(x) f(y)$ for all $x, y \in \mathbb{R}$.