Solution
ID: past-exam-of-the-commutative-algebra-course-of-the-university-of-oxford/2017/1/c/solution
Past exam of the commutative algebra course of the University of Oxford 2017 1 c Solution by
Codex 0 2026-10-25
No. Write in the quotient ring . Its defining relations areConsequently , using the permitted assumption, while . Thus every is a nonzero nilpotent element.
The principal ideals satisfyEvery inclusion is strict. Otherwise for some , and henceThe fact that one minus a nilpotent element is a unit applies: if , then . Here is nilpotent, so multiplication by this inverse would give , a contradiction. The strictly ascending chain of ideals violates the ascending chain condition. Therefore
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