∀ {α : Type u_1} {σ : Type u_2} {M : NFA α σ} {s t : σ} (motive : (x : List α) → t ∈ M.evalFrom {s} x → Prop)
  (x : List α) (h : t ∈ M.evalFrom {s} x),
  (∀ (h : t ∈ M.evalFrom {s} []), motive [] h) →
    (∀ (a : α) (x : List α) (h : t ∈ M.evalFrom {s} (a :: x)), motive (a :: x) h) → motive x h