| 释义 |
aleph-null The smallest infinite cardinal number. The cardinality of any set which can be put in one-to-one correspondence with the set of natural numbers. Such sets are said to be countably infinite or denumerable. Paradoxically the set of rational numbers between 0 and 1, the set of all rational numbers, and the set of natural numbers all have this same cardinality. The symbol ℵ0 is used.
|