Function Types
Injective: one-to-one
Surjective: all points in the codomain are connected to a point
range = codomain
Bijection: Surjective and Injective simultaneously
Inverse function
A function can not be invertible if the function itself isn’t bijective (cuz otherwise the inverse inverse of it wouldn’t go back to the original state)
(f∘g)(x)open paren f composed with g close paren open paren x close paren
(𝑓∘𝑔)(𝑥)
, which is equivalent to