Ideals and quotient rings

48 Views Asked by At

I am trying to show that

(R/I)/(J/I) is isomorphic to R/J

I and J are both ideals of the ring R, and I is a subset of J.

How do I begin this proof?

1

There are 1 best solutions below

0
On

Hint:

Define

$$\phi:R/I\to R/J\;\;,\;\;\phi(r+I):=r+J$$

Show this is a well defined function (i.e., $\;r+I=r'+I\implies r+J=r'+J\;$) and that it is an onto ring homomorphism. Now, what is its kernel? And then use the first isomorphism theorem.