RESEARCH ARTICLE
Attached primes and annihilators of top local cohomology modules defined by a pair of ideals
S. Karimia,
Sh. Payrovib a Department of Mathematics, Payame Noor University, 19395-3679, Tehran, Iran
b Department of Mathematics, Imam Khomeini International University, 34149-1-6818, Qazvin, Iran
Аннотация:
Assume that
$R$ is a complete Noetherian local ring and
$M$ is a non-zero finitely generated
$R$-module of dimension
$n=\dim(M)\geq 1$. It is shown that any non-empty subset
$T$ of
$\mathrm{Assh}(M)$ can be expressed as the set of attached primes of the top local cohomology modules
$H_{I,J}^n(M)$ for some proper ideals
$I,J$ of
$R$. Moreover, for ideals $I, J=\bigcap_ {\mathfrak p\in \mathrm{Att}_R(H_{I}^n(M))}\mathfrak p$ and
$J'$ of
$R$ it is proved that $T=\mathrm{Att}_R(H_{I,J}^n(M))=\mathrm{Att}_R(H_{I,J'}^n(M))$ if and only if
$J'\subseteq J$. Let
$H_{I,J}^n(M)\neq 0$. It is shown that there exists
$Q\in \mathrm{Supp}(M)$ such that
$\dim(R/Q)=1$ and
$H_Q^n(R/{\mathfrak p})\neq 0$, for each
$\mathfrak p \in \mathrm{Att}_R(H_{I,J}^n(M))$. In addition, we prove that if
$I$ and
$J$ are two proper ideals of a Noetherian local ring
$R$, then $\mathrm{Ann}_R(H_{I,J}^{n}(M))=\mathrm{Ann}_R(M/{T_R(I,J,M)})$, where
$T_R(I,J,M)$ is the largest submodule of
$M$ with $\mathrm{cd}(I,J,T_R(I,J,M))<\mathrm{cd}(I,J,M)$, here
$\mathrm{cd}(I,J,M)$ is the cohomological dimension of
$M$ with respect to
$I$ and
$J$. This result is a generalization of [1, Theorem 2.3] and [2, Theorem 2.6].
Ключевые слова:
associated prime ideals, attached prime ideals, top local cohomology modules.
MSC: 13D45,
14B15 Поступила в редакцию: 13.03.2017
Язык публикации: английский
DOI:
10.12958/adm429