MathDB
2018 VTRMC #3

Source: VTRMC 2018

December 3, 2018
functionalgebra

Problem Statement

Prove that there is no function f:NNf:\mathbb{N}\rightarrow \mathbb{N} such that f(f(n))=n+1.f(f(n))=n+1. Here N\mathbb{N} is the positive integers {1,2,3,}.\{1,2,3,\dots\}.