exact hmotive rfl
case mk.h
α : Type u_1
β : Type u_2
motive : Prop
L : List α
h✝ : Multiset.Nodup ⟦L⟧
f : (L_1 : List α) → ↑L_1 = { val := ⟦L⟧, nodup := h✝ }.val → β
h :
  ∀ (a b : List α) (ha : ↑a = { val := ⟦L⟧, nodup := h✝ }.val) (hb : ↑b = { val := ⟦L⟧, nodup := h✝ }.val),
    f a ha = f b hb
hmotive :
  ∀ {L_1 : List α} {hL : ↑L_1 = { val := ⟦L⟧, nodup := h✝ }.val},
    elim { val := ⟦L⟧, nodup := h✝ } f h = f L_1 hL → motive
⊢ motive
no goals