Representations with $Sp(1)^k$-reductions and quaternion-Kähler symmetric spaces

Claudio Gorodski, Francisco J. Gozzi

Published 2017-02-24Version 1

We classify non-polar irreducible representations of connected compact Lie groups whose orbit space is isometric to that of a representation of a finite extension of $Sp(1)^k$ for some $k>0$. It follows that they are obtained from isotropy representations of certain quaternion-K\"ahler symmetric spaces by restricting to the "non-$Sp(1)$-factor".