Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$ $\newcommand\empty{}$
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$

Example 4.7.3.2. Let $\aleph _0$ denote the first infinite cardinal (Example 4.7.2.10). Then a set $S$ is $\aleph _0$-small if and only if it is finite.