Graded components of local cohomology modules over polynomial rings
Abstract: Let $K$ be a field and let $R = K[X_1, \ldots, X_m]$ with $m \geq 2$. Give $R$ the standard grading. Let $I$ be a homogeneous ideal of height $g$. Assume $1 \leq g \leq m -1$. Suppose $Hi_I(R) \neq 0$ for some $i \geq 0$. We show (1) $Hi_I(R)_n \neq 0$ for all $n \leq -m$. (2) if Supp $Hi_I(R) \neq { (X_1, \ldots, X_m)}$ then $Hi_I(R)_n \neq 0$ for all $n \in \mathbb{Z}$. Furthermore if char $K = 0$ then $\dim_K Hi_I(R)_n$ is infinite for all $n \in \mathbb{Z}$. (3) $\dim_K Hg_I(R)_n$ is infinite for all $n \in \mathbb{Z}$. In fact we prove our results for $\mathcal{T}(R)$ where $\mathcal{T}(-)$ is a large sub class of graded Lyubeznik functors
Paper Prompts
Sign up for free to create and run prompts on this paper using GPT-5.
Top Community Prompts
Collections
Sign up for free to add this paper to one or more collections.