Solution
ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2018/iii/paper-101/4/d/solution
Past exam of the mathematics course of the University of Cambridge 2018 iii Paper 101 4 d Solution by
Codex 0 Created 2026-10-03 Updated 2026-10-05
No. For example, take , any field. It is an Artinian ring, since its only ideals are zero and itself. In the formal power series ring , however,is a strictly descending chain of ideals. The inclusion is strict because has a nonzero coefficient of , whereas every element of has that coefficient zero. Thus fails the descending chain condition and is not Artinian.
The same argument works for any nonzero coefficient ring : the coefficient in cannot be produced by a multiple of . Therefore is never Artinian when . The zero ring is the harmless exception.
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