Let R Z6Z What are the ideals of R For each ideal I of R de
Let R = Z/6Z. What are the ideals of R? For each ideal I of R, determine R/I.
Solution
Let R be a ring. An additive subgroup I of R that is also strongly closed under multiplication is called an ideal of R.
In the ring Z/6Z, the element r = 3 + 6Z of the ring R = Z/6Z generates a maximal ideal but is not irreducible since
r = r2 . The issue is that r is a zero-divisor
Now by homomorphism theorem the ideal in Z/6Z is of the form mz/nz where m is a divisor of n
So the only proper ideals are 2Z/6Z={0,2,4}
and 3Z/6Z = {0,3}
(b) Now R/I = Z/6Z /2 = 1/3
R/I = Z/6Z /4 = 2/3
