If f X---> Y is a function and if there is exactly one function g:Y---> X so that(adsbygoogle = window.adsbygoogle || []).push({});

f o g = id_y, the f is a bijection and g=f^-1. Do I need to use the axiom of choice to prove this theorem?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# The Axiom of Choice

**Physics Forums | Science Articles, Homework Help, Discussion**