No Natural Number between Number and Successor

Theorem
Let $\N$ be the natural numbers.

Let $n \in \N$.

Then no natural number $m$ exists strictly between $n$ and its successor $n + 1$:


 * $\neg \exists m \in \N: \paren {n < m < n + 1}$

That is:
 * If $n \le m \le n + 1$, then $m = n$ or $m = n + 1$.