∀ {α : Type u_1} (motive : (xs : Array α) → xs.size ≤ 1 → Prop) (xs : Array α) (h : xs.size ≤ 1),
  (∀ (h : { toList := [] }.size ≤ 1), motive { toList := [] } h) →
    (∀ (head : α) (h : { toList := [head] }.size ≤ 1), motive { toList := [head] } h) → motive xs h