suffices ∀ I ⊆ M.E, I = ∅ → M.Indep I by simpa
α : Type u_1
M✝ : Matroid α
E I B : Set α
k : ℕ∞
M : Matroid α
⊢ ∀ I ⊆ (M.truncateTo 0).E, (M.truncateTo 0).Indep I ↔ (loopyOn M.E).Indep I
α : Type u_1
M✝ : Matroid α
E I B : Set α
k : ℕ∞
M : Matroid α
⊢ ∀ I ⊆ M.E, I = ∅ → M.Indep I