# aleph-null

Definition from Wiktionary, the free dictionary

## English[edit]

### Proper noun[edit]

- (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*.

#### Synonyms[edit]

- (first transfinite cardinal number): aleph-naught, aleph-nought, aleph-zero, ℵ₀