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HairOnABiscuit December 9th, 2009 06:04 AM

Let A and B be ideals of a ring R. Prove that

(a) is an ideal of R
(b) is an ideal of R

cknapp December 9th, 2009 06:25 AM

Re: Ideal
Check what happens if you multiply r (an arbitrary ring element) by an element of or an element of A+B.

HairOnABiscuit December 12th, 2009 06:46 AM

Re: Ideal
Ok for part a) i need to show using and .

Proof: let and , . How do i go form here to show that and ?

mAraujo December 12th, 2009 01:11 PM

Re: Ideal

Originally Posted by HairOnABiscuit
How do i go form here to show that and ?

remember A and B are ideals of R.

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