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The first Hebrew letter with a zero subscript, counting the whole numbers.
Also known as: Aleph naught, Aleph zero, Countable infinity
Aleph-null is the size of the set of natural numbers — the smallest infinite quantity. Cantor chose a Hebrew letter deliberately, and the subscript counts upwards through larger infinities, which is the notation's real content: there is more than one infinity and they can be indexed.
Denotes the cardinality of the set of natural numbers, the smallest infinite cardinal number.
Contexts: Mathematics
Is the first of an indexed sequence of infinite cardinals, so the subscript is a genuine counter rather than decoration.
Contexts: Mathematics
A Hebrew letter of two diagonal strokes joined by a bar, with a small zero set at its lower right.
Both stand for infinity; only one of them distinguishes sizes of it.