Example: Let f: A-B. A,B and f are defined as , A: [1,2,3], B[5,6,7,8], f[(1,5),(2,8),(3,6)] Solution: No element of A has more than 1 image, every element of A has more than 1 image, every element of A has a different image in B and no 2 or more elements of A have the same image in B. Therefore f is an one to one function.
