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Aug 12, 2015 at 19:20 comment added lokodiz @JasonStarr: Sorry, I got confused by the fact that $\text{pdim}_{\Bbbk[x]} \Bbbk [x]/\langle x^2 \rangle = \infty$.
Aug 12, 2015 at 18:07 comment added Jeremy Rickard In the non-commutative case I'm not sure whether every map from an $MCM$ module to a module of finite injective dimension factors through a projective module. I don't think the argument in my answer generalizes straightforwardly to prove this, but I'll think about it.
Aug 12, 2015 at 15:10 history edited Jason Starr CC BY-SA 3.0
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Aug 12, 2015 at 15:03 history edited Jason Starr CC BY-SA 3.0
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Aug 12, 2015 at 14:47 comment added Jason Starr @Simon: So that I understand, are you hypothesizing that $R$ has finite injective dimension as an $R$-module (the usual definition of Gorenstein), or are you hypothesizing that every $R$-module has finite injective dimension? Certainly $R=k[x]/\langle x^2\rangle$ has finite injective dimension as an $R$-module: it is an injective $R$-module.
Aug 12, 2015 at 14:41 history edited Jason Starr CC BY-SA 3.0
Added hypothesis on injective dimension.
Aug 12, 2015 at 14:37 comment added lokodiz Isn't $\text{gldim } \Bbbk[x]/\langle x^2 \rangle = \infty$?
Aug 12, 2015 at 14:26 history edited Jason Starr CC BY-SA 3.0
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Aug 12, 2015 at 14:03 history edited Jason Starr CC BY-SA 3.0
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Aug 12, 2015 at 13:57 history edited Jason Starr CC BY-SA 3.0
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S Aug 12, 2015 at 13:50 history answered Jason Starr CC BY-SA 3.0
S Aug 12, 2015 at 13:50 history made wiki Post Made Community Wiki by Jason Starr