 Axiom of countability

The Axiom of Countability is a principle in set theory that deals with the properties of countable sets. In the context of set theory, a set is considered countable if it can be put into a one-to-one correspondence with the set of natural numbers (i.e., it can be enumerated). Specifically, the Axiom of Countability generally refers to the notion that certain mathematical structures possess countable bases or countable properties.