Annihilator of Top Local Cohomology and Lynch's Conjecture

Abstract

Let $R$ be a commutative Noetherian ring, $\mathfrak{a}$ a proper ideal of $R$ and $N$ a non-zero finitely generated $R$-module with $N\ne \mathfrak{a}N$. Let $d$ (respectively $c$) be the smallest (respectively greatest) non-negative integer $i$ such that the local cohomology $H_{\mathfrak{a}}^i(N)$ is non-zero. In this paper, we provide sharp bounds under inclusion for the annihilators of the local cohomology modules $H_{\mathfrak{a}}^d(N)$, $H_{\mathfrak{a}}^c(N)$ and these annihilators are computed in certain cases. Also, we construct a counterexample to Lynch's conjecture.

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