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By virtue the Griffith's paper and subsequently e.g. Goto's paper several examples of several desired class of Noetherian normal domains with specific finite length local cohomologies are constructed using the Bourbaki ideals. In order to compute some properties of these rings with Macaulay 2, I need to compute their Bourbaki ideals. does there exist any manuscript or any way to make this computation possible or easier?

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  • $\begingroup$ Just out of curiosity, what is a Bourbaki ideal? $\endgroup$
    – abx
    Nov 29, 2014 at 7:41
  • $\begingroup$ @abx: Let e.g. $R=K[X_1,...,X_n]$. Then the the Bourbaki ideal associated to an $R$-module $M$ is an ideal $I$ arising from an exact sequence $0\rightarrow F\rightarrow M\rightarrow I\rightarrow 0$ where $F$ is a finitely generated graded free $R$-module $\endgroup$
    – Aurora
    Nov 29, 2014 at 7:53
  • $\begingroup$ I am not so sure if there is an easy way to convert a module into an ideal on Macaulay2. If the module $M$ has a rank, maybe even torsion free, then probably a generic choice of minimal generating set would produce a free submodule $F$ of rank one less than $M$. But here, your ideal $I$ may not be unique since it'd depend on the choice of the generators for $F$. $\endgroup$
    – Youngsu
    Nov 29, 2014 at 22:08
  • $\begingroup$ @Youngsu: Yes, in the Bourbaki exact sequence mentioned in my previous comment, as I know, $M$ should be torsion free and the free module $F$ satisfies $\text{rank}(F)=\text{rank}(M)-1$. Would you please kindly explain how can I obtain an ideal $I$ from a generic choice of minimal generating set of $M$ by means of Macaulay 2? $\endgroup$
    – Aurora
    Nov 30, 2014 at 0:44
  • $\begingroup$ Let me try. Would you mind posting an example you have in mind? $\endgroup$
    – Youngsu
    Nov 30, 2014 at 1:00

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