Aleph one

smallest uncountable cardinal number

Aleph one, written as , is an infinite cardinal number following aleph null ().[1] It is the cardinality (size) of the set of numbers of possible arrangements for all countably infinite sets. Under continuum hypothesis, it is also the cardinality of the real numbers.[2] Aleph one is followed by aleph two, .

Related pagesEdit


  1. "Comprehensive List of Set Theory Symbols". Math Vault. 2020-04-11. Retrieved 2020-09-05.
  2. Weisstein, Eric W. "Aleph-1". Retrieved 2020-09-05.