∀ {α : Type u_1} {M : Matroid α} {X : Set α} (motive : (∃ e ∈ X, M.IsNonloop e ∧ X ⊆ M.closure {e}) → Prop)
  (x : ∃ e ∈ X, M.IsNonloop e ∧ X ⊆ M.closure {e}),
  (∀ (e : α) (heX : e ∈ X) (he : M.IsNonloop e) (hXe : X ⊆ M.closure {e}), motive ⋯) → motive x