The cardinality of the integers, whole numbers, and rationals. See SetTheory and/or TransfiniteCardinality for more. http://jeff560.tripod.com/aleph.gif is also known as aleph-null, aleph-zero. See also SurrealNumbers by DonaldErvinKnuth ---- An old math joke related to the concept: AlephNought bottles of beer on the wall, AlephNought bottles of beer, Take one down, pass it around, AlephNought bottles of beer on the wall. ---- CategoryMath