Let $X$ be a normal variety over $\mathbb{C}$ , and let $U$ be a open subset of $X$, then there is an long exact sequence for singular or De Rham cohomology with compact support that relates the cohomology groups of $X$,$U$ and $X - U$.
Did exist some (maybe partial) results about sheaf cohomology in the same situation? Im interested in the particular situation when $X$ is a normal variety with an effective action of a reducible algebraic group defined over $\mathbb{C}$.
Thanks in advance for any reference or comment!