One to One For the function f : A -> B, we say f is one-to-one if no single element y of B can be f(x) for more than one x in A Onto Function For the function f : A -> B, if f(A) = B (the range and codomain of f are equal and every element of the codomain is actually one of the values of the functions), the function f is said to be a onto function Bijection Function For the function f: A B, f is bijection if f is one-to-one as well onto function.
