Ring $R_{ 115 }$

Description:

Let $L$ be a field, $K=L((Y))$, and define an endomorphism of $K$ by $\alpha(Y)=Y^n$. Let $S=K[X;\alpha]$ be the twisted power series with $Xk:=\alpha(k)X$. The ring is $R=T(S, E)$, where $E$ is $S$'s minimal left cogenerator. $E$ can be realized as the set $[X^{-1}]$... ( to be completed)

Keywords power series ring trivial extension twisted (skew) polynomial ring