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cubixguy77
Nov23-08, 08:24 PM
1. The problem statement, all variables and given/known data
Prove that the intersection of any set of ideals of a ring is an ideal.


2. Relevant equations
A nonempty subset A of a ring R is an ideal of R if:
1. a - b ε A whenever a, b ε A
2. ra and ar are in A whenever a ε A and r ε R


3. The attempt at a solution
My guess is that i need to start with a collection of ideals,
write a representation of the form of the intersection of those ideals,
upon which i can take two generic elements and apply the ideal test above

Putting this into symbols seems to be the tricky part for me.
Thanks.

morphism
Nov23-08, 08:50 PM
You don't need a representation of the form of the intersection. Just apply the definition directly. For example, to apply 1, take a & b in the intersection. What can you say about a-b?