Trichotomy Law for Real Numbers/Proof 2
Theorem
The real numbers obey the trichotomy law.
That is, $\forall a, b \in \R$, exactly one of the following holds:
| \((1)\) | $:$ | $a$ is greater than $b$: | \(\ds a > b \) | ||||||
| \((2)\) | $:$ | $a$ is equal to $b$: | \(\ds a = b \) | ||||||
| \((3)\) | $:$ | $a$ is less than $b$: | \(\ds a < b \) |
Proof
$\le$ is a total ordering on $\R$.
The trichotomy follows directly from Trichotomy Law.
$\blacksquare$