Let A = {a1, a2} and B = {b1, b2, b3}. Let the function f:A → B be given by the following set of ordered pairs: f = {(a1,b2),(a2,b3)}.
List as a set of ordered pairs a function g: B→A with the property that for all a in A g(f(a)) = a, and show that this property holds. Note that since the domain of g is B, you need to make sure your function g maps each element in B to some element in A.