Definition 5 (page 61): A function f is said to be one-to-one (injective) iff f(x) = f(y) implies that x = y for all x and y in the domain of f.
Definition 7 (page 62): A function f from set A to set B is called onto (surjective) iff for every element b in B there is an element a in A with f(a) = b.
A function is a bijection (one-to-one correspondence) if it is both an injection and a surjection
Example 1.
Example 2.
Example 3.
Theorem 1.
Example 4
Example 5
Example 6
Corollary 1
Theorem 3
Example 7
Example 8