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verification. (March 2024) |
In set theory, a set is called hereditarily countable if it is a countable set of hereditarily countable sets.
The inductive definition above is well-founded and can be expressed in the language of first-order set theory.
A set is hereditarily countable if and only if it is countable, and every element of its transitive closure is countable. [1]
This article needs additional citations for
verification. (March 2024) |
In set theory, a set is called hereditarily countable if it is a countable set of hereditarily countable sets.
The inductive definition above is well-founded and can be expressed in the language of first-order set theory.
A set is hereditarily countable if and only if it is countable, and every element of its transitive closure is countable. [1]