Aleph Zero equals Cardinality of Naturals

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Theorem

$\aleph_0 = \card \N$

where

$\aleph$ denotes the aleph mapping,
$\card \N$ denotes the cardinality of $\N$.


Proof

\(\ds \aleph_0\) \(=\) \(\ds \card {\aleph_0}\) Cardinal of Cardinal Equal to Cardinal
\(\ds \) \(=\) \(\ds \card {\omega}\) Definition of Aleph Mapping
\(\ds \) \(=\) \(\ds \card {\N}\) Definition of Natural Numbers

$\blacksquare$


Sources