# Discrete Mathematics/Axiom of choice

Jump to: navigation, search

Axiom of choice:

If ${\displaystyle f:A\rightarrow B}$ is a surjective map, then there exists a map ${\displaystyle g:B\rightarrow A}$ such that ${\displaystyle f\circ g}$ is the identity (trivial) map.

Lemma: Every set can be well-ordered.