MathDB
Functional inequality

Source: IZHO2016

January 16, 2016
inequalities

Problem Statement

Find all k>0k>0 for which a strictly decreasing function g:(0;+)(0;+)g:(0;+\infty)\to(0;+\infty) exists such that g(x)kg(x+g(x))g(x)\geq kg(x+g(x)) for all positive xx.