Abstract:
Let $R$ be a commutative ring with 1, $2\in R^*$, and $l\ge 3$. We describe subgroups of the general linear group $\mathrm{GL}(n,R)$ containing the split elementary orthogonal group $\mathrm{EO}(2l,R)$. For every
intermediate subgroup $H$ there exists a unique maximal ideal $A\unlhd R$ such that $E(2l,R,A)\le H$, and moreover $H$ normalises $\mathrm{EO}(2l,R)E(2l,R,A)$. In the case when $R=K$ is a field, similar results have been obtained earlier by Dye, King, Li Shangzhi and Bashkirov.