Kerodon

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

Example 4.7.1.10. The set of nonnegative integers $\operatorname{\mathbf{Z}}_{\geq 0} = \{ 0 < 1 < 2 < \cdots \} $ is well-ordered (with respect to its usual ordering). Its order type is an infinite ordinal, which we denote by $\omega $.