Left and Right Implication Arrows
Another way to display the arrows for right and left implication instead of using
$\Rightarrow$
, $\Leftarrow$
and $\Leftrightarrow$
which produces $\Rightarrow$, $\Leftarrow$ and $\Leftrightarrow$ respectively, you can use
$\implies$
for $\implies$, $\impliedby$
for $\impliedby$ and $\iff$
for $\iff$
The latter of which produces longer arrows which may be more desirable to some.