∀ (G : Type u_1) [inst : AddGroup G] {X : Type u_2} [inst_1 : AddAction G X] (a : X)
  (motive : ↑(Set.Ici (AddAction.stabilizer G a)) → Prop) (x : ↑(Set.Ici (AddAction.stabilizer G a))),
  (∀ (val : AddSubgroup G) (hH : val ∈ Set.Ici (AddAction.stabilizer G a)), motive ⟨val, hH⟩) → motive x