∀ {α : Type u} {β : α → Type v} {motive : (a : Std.DTreeMap.Internal.Impl α β) → a.Balanced → Prop}
  {motive_1 :
    {a : Std.DTreeMap.Internal.Impl α β} → (t : a.Balanced) → Std.DTreeMap.Internal.Impl.Balanced.below t → Prop}
  {a : Std.DTreeMap.Internal.Impl α β} {t : a.Balanced} (t_1 : Std.DTreeMap.Internal.Impl.Balanced.below t),
  motive_1 ⋯ ⋯ →
    (∀ {sz : ℕ} {k : α} {v : β k} {l r : Std.DTreeMap.Internal.Impl α β} (a : l.Balanced) (a_1 : r.Balanced)
        (a_2 : Std.DTreeMap.Internal.Impl.BalancedAtRoot l.size r.size) (a_3 : sz = l.size + 1 + r.size)
        (ih : Std.DTreeMap.Internal.Impl.Balanced.below a) (a_ih : motive l a)
        (ih_1 : Std.DTreeMap.Internal.Impl.Balanced.below a_1) (a_ih_1 : motive r a_1), motive_1 ⋯ ⋯) →
      motive_1 t t_1