\begin{definition}[Definition:Perfect Field/Definition 2]
Let $F$ be a field.
$F$ is a '''perfect field''' {{iff}} one of the following holds:
:$\Char F = 0$
:$\Char F = p$ with $p$ prime and $\Frob$ is an automorphism of $F$
where:
:$\Char F$ denotes the characteristic of $F$
:$\Frob$ denotes the Frobenius endomorphism on $F$
\end{definition}