Given sets x and y , define fun(x, y ) to be the set of all functions from x to y . that is, f ? fun(x, y ) ? f : x ? y is a function. let x = {1, 2} and y = {a, b}. list all the elements of fun(x, y ). example: the function f defined by f(1) = b and f(2) = b is an element of fun(x, y ).