Question
On the set of integers $\mathbb{Z}$, define $f: \mathbb{Z} \to \mathbb{Z}$ as $f(n) = \begin{cases} \frac{n}{2}, & n \text{ is even} \\ 0, & n \text{ is odd} \end{cases}$. Then $f$ is
On the set of integers $\mathbb{Z}$, define $f: \mathbb{Z} \to \mathbb{Z}$ as $f(n) = \begin{cases} \frac{n}{2}, & n \text{ is even} \\ 0, & n \text{ is odd} \end{cases}$. Then $f$ is