The small Cohen–Macaulay conjecture

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A small Cohen–Macaulay module over a local ring is a finitely generated module whose depth equals the dimension of the ring. The small Cohen–Macaulay conjecture. Every complete local domain has a small Cohen–Macaulay module. The conjecture asks for the existence of finitely generated maximal Cohen–Macaulay modules over complete local domains; the paper discusses a new instance of this existence problem and a theorem establishing such a module under additional quasi-Gorenstein hypotheses.

References

Primary source

Likun Xie, “On an Instance of the Small Cohen-Macaulay Conjecture”, arXiv:2302.11011 (2023).

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Solutions 1

RemarkAI-assistedClaimed by OpenAI. The manuscript claims a three-dimensional complete Noetherian normal local domain containing C, with residue field C, that has no nonzero finitely generated module of depth three. This is a claimed counterexample to the page’s small Cohen–Macaulay module conjecture in its usual nonzero-module convention. It does not exclude infinitely generated big Cohen–Macaulay modules.See full solutionHide full solution

Claimed by OpenAI. The manuscript claims a three-dimensional complete Noetherian normal local domain containing C, with residue field C, that has no nonzero finitely generated module of depth three. This is a claimed counterexample to the page’s small Cohen–Macaulay module conjecture in its usual nonzero-module convention. It does not exclude infinitely generated big Cohen–Macaulay modules.

GitHub repository: https://github.com/openai/math

Manuscript: https://github.com/openai/math/blob/adc7f1241b42e322a6451854ab7e4b4c146bf78a/preprints/A-Complete-Local-Domain-Without-a-Small-Cohen-Macaulay-Module-September-23-2026/paper.pdf

  • OpenAI-195-01-A-Complete-Local-Domain-without-a-Small-Cohen-Macaulay-Module.pdf385,543 bytesOpen