Guralnick, Kunyavskii, Plotkin and Shalev have shown that the solvable
radical of a finite group $G$ can be characterized as the set of all $x\in G$
such that $$ is solvable for all $y\in G$. We prove two generalizations of
this result. Firstly, it is enough to check the solvability of $$ for
every $p$-element $y\in G$ for every odd prime $p$. Secondly, if $x$ has odd
order, then it is enough to check the solvability of $$ for every
2-element $y\in G$.Comment: 17 page

Guest, Simon