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4 votes
1 answer
158 views

injective hulls in mixed characteristic

Let $R=\underleftarrow\lim (R/\mathfrak m^i)$ be a complete local ring, with residue field $k=R/\mathfrak m$, and let's assume that $R$ is Noetherian. If $R$ is a $k$-algebra, then I believe that ...
André Henriques's user avatar
2 votes
1 answer
112 views

Example of non injective module over Noetherian local ring with trivial vanishing against residue field?

Is there an example of a module $M$ over a commutative Noetherian local ring $(R,\mathfrak m, k)$ such that $\text{Ext}_R^{>0}(k, M)=0$ but $M$ is not an injective $R$-module? I know that for such ...
Alex's user avatar
  • 480
2 votes
0 answers
111 views

When does a local Cohen–Macaulay ring admit a non-zero finitely generated maximal Cohen–Macaulay module of finite injective dimension?

Let $(R,\mathfrak m)$ be a local Cohen–Macaulay ring. Then, it is well- nown that there exists a non-zero finitely generated $R$-module of finite injective dimension; for instance $\operatorname{Hom}...
strat's user avatar
  • 361