rw [← indep_singleton, comap_indep_iff, image_singleton, indep_singleton,
  and_iff_left (injOn_singleton _ _)]
α : Type u_1
β : Type u_2
M✝ N : Matroid α
e f✝ : α
B L L' I X Y Z F C K : Set α
M : Matroid β
f : α → β
⊢ (M.comap f).Nonloop e ↔ M.Nonloop (f e)
no goals