Central commutator has no torsion from an abelian Sylow subgroup (source code)

= Central commutator has no torsion from an abelian Sylow subgroup
{title2=$p\nmid|G'\cap Z(G)|$}

If a <Sylow p-subgroup> $P$ is abelian, a hypothetical central subgroup $Q\leq G'$ of order $p$ has a nontrivial linear character extending to $P$. Inducing this extension to $G$ gives a character of degree prime to $p$, hence an irreducible constituent of such degree. On $Q$ its <determinant character> is a nontrivial power of the chosen linear character, but every determinant character is trivial on $G'$. This contradiction proves the displayed restriction.