∀ (M : Type u_1) {α : Type u_2} {inst : Group M} {inst_1 : MulAction M α} (n : ℕ)
  [self : MulAction.IsMultiplyPreprimitive M α n] {s : Set α},
  s.encard + 1 = ↑n → MulAction.IsPreprimitive ↥(fixingSubgroup M s) ↥(SubMulAction.ofFixingSubgroup M s)