simp
case h.e'_3
ι : Type u_1
α : Type u_2
M : Matroid α
B I J X X' Y Y' F : Set α
Xs Ys Js Is : ι → Set α
i j : ι
e f : α
inst✝ : Nontrivial ι
h : M.ModularFamily Xs
i₀ : ι
⊢ Xs i₀ = ⋂ i ∈ {i₀}, Xs i
no goals