Finite group actions on the non-minimal nilpotent orbit closures in type A

Source abstract

We study quotients of the closures of the nilpotent orbits of type A by finite groups of inner automorphisms. Assuming the nilpotent orbit is not minimal, we show that the Q-factorial terminalizations of quotients of nilpotent orbit closures are precisely the quotients of the symplectic resolutions of the orbit closures. This identifies the Mori fan of each Q-factorial terminalization of the quotient with the Mori fan of a symplectic resolution of the orbit closure.