Onto Or Surjective Function

Onto or Surjective function

Onto or Surjective function
Definition
Properties
Examples
A function f: X -> Y is said to be onto or surjective if every element of Y has a pre-image in X
Every onto function has a right inverse
If f: X -> Y is onto and X is finite, then Y is finite
f: R -> R defined by f(x) = 2x + 3 is surjective
f: Z -> Z defined by f(n) = 2n is not surjective