StevenXClontz’s Twitter Archive—№ 8,653

@Thalesdisciple @EmiDoesMath @pwr2dppl Let A be infinitely many socks, then f could be a surjection mapping each sock in A to a pair in B. Then an injection from B to A would choose a sock from each of the infinite pairs in B. So you definitely need some form of choice, and I wouldn't be surprised if it's equivalent.