Beth number

In set theory, a **Beth number** is a hierarchy of infinite cardinal numbers that are used to describe the sizes of infinite sets. They are denoted by the symbol \( \beth \) followed by a subscript indicating the ordinal number in the sequence. The definition of Beth numbers is as follows: 1. \( \beth_0 \) is defined to be \( \aleph_0 \), the cardinality of the set of natural numbers, which is the smallest infinite cardinal.