Definition:Countable Set

Definition
Let $S$ be a set.

Also see

 * Equivalence of Definitions of Countable Set
 * Surjection from Natural Numbers iff Countable
 * Countable Set equals Range of Sequence


 * Definition:Finite Set
 * Definition:Infinite Set
 * Definition:Uncountable Set


 * Sufficient Conditions for Uncountability