In 1987 F.-O. Schreyer conjectured that a local ring R has finite Cohen-Macaulay type if and only if the completion R has finite Cohen-Macaulay type. We prove the conjecture for excellent Cohen-Macaulay local rings and also show by example that it can fail in general.
Local Rings of Finite Cohen–Macaulay Type
✍ Scribed by Roger Wiegand
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 191 KB
- Volume
- 203
- Category
- Article
- ISSN
- 0021-8693
No coin nor oath required. For personal study only.
✦ Synopsis
Let R, m be a local Cohen᎐Macaulay ring whose m-adic completion R has an isolated singularity. We verify the following conjecture of F.-O. Schreyer: R has finite Cohen᎐Macaulay type if and only if R has finite Cohen᎐Macaulay type. We ww xx Ž . also show that the hypersurface k x , . . . , x r f has finite Cohen᎐Macaulay 0 d s ww xx Ž . s type if and only if k x , . . . , x r f has finite Cohen᎐Macaulay type, where k 0 d
is the separable closure of the field k.
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