Fixed points of $p$-toral groups acting on partition complexes

Abstract

We consider the action of $p$-toral subgroups of $U(n)$ on the unitary partition complex $\mathcal L_n$. We show that if $H\subseteq U(n)$ is $p$-toral and has noncontractible fixed points on $\mathcal L_n$, then the image of $H$ in the projective unitary group $U(n)/S^{1}$ is an elementary abelian $p$-group.