A graph related to Euler $\varphi$ function

Nima Ghanbari, Saeid Alikhani

Euler function $\varphi (n)$ is the number of positive integers less than $n$ and relatively prime to $n$. Suppose that ${\varphi }^1(n)=\varphi (n)$ and ${\varphi }^i(n)=\varphi ({\varphi }^{i-1}(n))$. Let $A\subseteq \mathbb{N…