aleph-null

Proper noun. (set theory) The first of the transfinite cardinal numbers; corresponds to the number of positive integers, also called ''natural numbers''. Georg Cantor showed that even all the rational numbers could be put in one-to-one correspondence with them, and are therefore ''countable'', ''enumerable'' or ''denumerable''.

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This entry was last updated on RefTopia from its source on 3/20/2012.