# Aleph-zero

From Encyclopedia of Mathematics

2020 Mathematics Subject Classification: *Primary:* 03E10 [MSN][ZBL]

A cardinal number which is the cardinality of all countably-infinite sets (cf Countable set). Denoted by $\aleph_0$.

**How to Cite This Entry:**

Aleph-zero.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Aleph-zero&oldid=35818

This article was adapted from an original article by P.S. Aleksandrov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article