On generalized completion homology modules

Abstract

Let $I$ be an ideal of a commutative Noetherian ring $R$. Let $M$ and $N$ be any $R$-modules. We define the generalized completion homology modules $L_i{\Lambda }^I(N,M)$, for $i\in \mathbb{Z}$, as the homologies of the complex $\underset{⟵}{\lim }(N/I^{s}N{\otimes }_R{F}_{\cdot }^R)$. Here $F_{\cdot }^R$ denote a flat resolution of $M$. In this article we will prove the vanishing and non-vanishing properties of $L_i{\Lambda }^I(N,M)$. We denote $H_I^i(N,M)$ (resp. $U_i^I(N,M)$) by the generalized local cohomology modules (resp. the generalized local homology modules). As a technical tool we will construct several natural homomorphisms of $L_i{\Lambda }^I(N,M)$, $H_I^i(N,M)$ and $U_i^I(N,M)$. We will investigate when these natural homomorphisms are isomorphisms. Moreover if $M$ is Artinian and $N$ is finitely generated then it is proven that $L_i{\Lambda }^I(N,M)$ is isomorphic to $U_i^I(N,M)$ for each $i\in \mathbb{Z}$. The similar result is obtained for $H_I^i(N,M)$. Furthermore if both $M$ and $N$ are finitely generated with $c=\grade(I,M)$. Then we are able to prove several necessary and sufficient conditions such that $H_I^i(M)=0$ for all $i\ne c.$ Here $H_I^i(M)$ denote the ordinary local cohomology module.

17 pages

References in corpus (1)

• On Endomorphism Rings of Local Cohomology Modules