Codex > Ordinals (Set Theory)
🅟 Mar 06, 2026
🅤 Jul 09, 2026
Definition 1. A set $X$ is finite if there is a bijection from $X$ to a natural number. $X$ is infinite if it is not finite.
Definition 1.
A set $X$ is finite if there is a bijection from $X$ to a natural number. $X$ is infinite if it is not finite.