2000 character limit reached
On an endomorphism ring of local cohomology (1208.2098v1)
Published 10 Aug 2012 in math.AC
Abstract: Let $I$ be an ideal of a local ring $(R,\mathfrak m)$ with $d = \dim R.$ For the local cohomology module $Hi_I(R)$ it is a well-known fact that it vanishes for $i > d$ and is an Artinian $R$-module for $i = d.$ In the case that the Hartshorne-Lichtenbaum Vanishing Theorem fails, that is $Hd_I(R) \not= 0,$ we explore its fine structure. In particular, we investigate its endomorphism ring and related connectedness properties. In the case $R$ is complete we prove - as a technical tool - that $Hd_I(R) \simeq Hd_{\mathfrak m}(R/J)$ for a certain ideal $J \subset R.$ Thus, properties of $Hd_I(R)$ and its Matlis dual might be described in terms of the local cohomology supported in the maximal ideal.