3.7 Arrows

$\leftarrow$, $\gets$, $\Leftarrow$, $\rightarrow$, $\to$,
$\Rightarrow$, $\leftrightarrow$, $\Leftrightarrow$, $\mapsto$,
$\leftharpoonup$, $\leftharpoondown$, $\rightleftharpoons$,
$\longleftarrow$, $\Longleftarrow$, $\longrightarrow$,
$\Longrightarrow$, $\longleftrightarrow$, $\Longleftrightarrow$,
$\iff$, $\longmapsto$, $ \rightharpoonup$, $\rightharpoondown$,
$\uparrow$, $\Uparrow$, $\downarrow$, $\Downarrow$, $\updownarrow$,
$\Updownarrow$, $\nearrow$, $\searrow$, $\swarrow$, $\nwarrow$

$\leftarrow $, $\gets $, $\Leftarrow $, $\rightarrow $, $\to $, $\Rightarrow $, $\leftrightarrow $, $\Leftrightarrow $, $\mapsto $, $\leftharpoonup $, $\leftharpoondown $, $\rightleftharpoons $, $\longleftarrow $, $\Longleftarrow $, $\longrightarrow $, $\Longrightarrow $, $\longleftrightarrow $, $\Longleftrightarrow $, $\iff $, $\longmapsto $, $ \rightharpoonup $, $\rightharpoondown $, $\uparrow $, $\Uparrow $, $\downarrow $, $\Downarrow $, $\updownarrow $, $\Updownarrow $, $\nearrow $, $\searrow $, $\swarrow $, $\nwarrow $