MathDB
f (x + 1) >= f (x) + 1, f (x y) >=ge f (x)f (y)

Source: 2016 Saudi Arabia IMO TST , level 4+, II p2

July 29, 2020
algebraFunctional inequality

Problem Statement

Find all functions f:RRf : R \to R satisfying the conditions: 1. f(x+1)f(x)+1f (x + 1) \ge f (x) + 1 for all xRx \in R 2. f(xy)f(x)f(y)f (x y) \ge f (x)f (y) for all x,yRx, y \in R