Sandwich classification for $G{L}_n(R)$, $O_{2n}(R)$ and $U_{2n}(R,\Lambda )$ revisited

Raimund Preusser

Let $n$ be a natural number greater or equal to $3$, $R$ a commutative ring and $\sigma \in G{L}_n(R)$. We show that $t_{kl}({\sigma }_{ij})$ (resp. $t_{kl}({\sigma }_{ii}-{\sigma }_{jj}))$ where $i\ne j$ and $k…