∀ {α : Sort u_1} {r : α → α → Prop} {motive : {a b : α} → Relation.ReflTransGen r a b → Prop} {a b : α}
  (h : Relation.ReflTransGen r a b),
  (∀ (a : α), motive ⋯) →
    (∀ {a b : α} (h : r a b), motive ⋯) →
      (∀ {a b c : α} (h₁ : Relation.ReflTransGen r a b) (h₂ : Relation.ReflTransGen r b c),
          motive h₁ → motive h₂ → motive ⋯) →
        motive h