2 problems

Let $n$ be a natural number, let $G(\mathbb{Z}_n)$ be a unit graph, and let $H$ be a $|V|\times|E|$ incidence matrix of $G(\mathbb{Z}_n)$. Let $\phi(n)$ denote Euler's totient func…

Let $n$ be a natural number, and let $G(\mathbb{Z}_n)$ be the unit graph. Write $U(\mathbb{Z}_n)$ for its set of units, $N_U(\mathbb{Z}_n)$ for its set of non-units, and…