Solution
= Solution
If $x$ is a <fixed point> of $f$, then
$$
g(\sigma x)=\sigma f\sigma^{-1}(\sigma x)
=\sigma f(x)=\sigma x.
$$
Conversely, applying the same argument to $f=\sigma^{-1}g\sigma$ transports every fixed point of $g$ back to one of $f$. Thus the bijection $\sigma$ restricts to a bijection between the two fixed-point sets, so <conjugate functions> have the same number of fixed points.