Injective, surjective, bijective – and a bit about infinity
Listen, there are no measurements in infinity. You humans have got such limited little minds.
The Doctor in Doctor Who and the Masque of Mandragora
We have seen that sets are building blocks of mathematics and have said a little about functions between sets. We shall now look more closely at functions. For functions f : X → Y we define injective, surjective and bijective functions. These definitions allow us to compare sets and in the case of bijective functions allow us to ...