Published online by Cambridge University Press: 20 November 2018
If $C=C\left( R \right)$ denotes the center of a ring
$R$ and
$g\left( x \right)$ is a polynomial in
$C\left[ x \right]$, Camillo and Simón called a ring
$g\left( x \right)$-clean if every element is the sum of a unit and a root of
$g\left( x \right)$. If
$V$ is a vector space of countable dimension over a division ring
$D$, they showed that
$\text{en}{{\text{d}}_{\,D}}V$ is
$g\left( x \right)$-clean provided that
$g\left( x \right)$ has two roots in
$C\left( D \right)$. If
$g\left( x \right)=x-{{x}^{2}}$ this shows that
$\text{en}{{\text{d}}_{\,D}}V$ is clean, a result of Nicholson and Varadarajan. In this paper we remove the countable condition, and in fact prove that
$\text{en}{{\text{d}}_{\,R}}M$ is
$g\left( x \right)$-clean for any semisimple module
$M$ over an arbitrary ring
$R$ provided that
$g\left( x \right)\in \left( x-a \right)\left( x-b \right)C\left[ x \right] $ where
$a,b\in C$ and both
$b$ and
$b-a$ are units in
$R$.