rwa [preimage_image_eq _ f.injective] at hI
α : Type u_1
β : Type u_2
f✝ : α → β
E I✝ s : Set α
M : Matroid α
N : Matroid β
f : ↑M.E ↪ β
I : Set ↑M.E
hI : M.Indep ↑(⇑f ⁻¹' (⇑f '' I))
⊢ M.Indep ↑I
no goals