Problem 4 Let us endow the finite set Z6 := {0,1,2,3,4,5} with the operations +: Z6 xZ6> Z6 (x,y)H r6(x+y) and .: Z6 x Z6y Z6 (x,y)Hr6(xy) where, for an integer a, rs(a) is the remainder in the Euclidean division of a by 6 i.e. the unique integer 0 < rs(a) < 6 such that a = 6 x q + rs(a).
Show that Z6 fails to satisfy all the axioms for a field. (Hint: look at axioms 7 and 8 What is the multiplicative inverse of 2?)