For an integer n > 1, let G = Un, the group of units in Zn; that is, the set of all [a] in Zn that have multiplicative inverses. Prove that Un is a group with respect to multiplication.
For an integer n > 1, let G = Un, the group of units in Zn; that is, the set of all [a] in Zn that have multiplicative inverses. Prove that Un is a group with respect to multiplication.