rintro e ⟨⟨_,⟨i,hi,rfl⟩,hi'⟩ ,⟨_,⟨j,hj,rfl⟩,hj'⟩⟩
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
h : M.SkewFamily Xs
A : Set ι
⊢ (⋃ i ∈ A, Xs i) ∩ ⋃ i ∈ Aᶜ, Xs i ⊆ M.cl ∅
case intro.intro.intro.intro.refl.intro.intro.intro.refl
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
h : M.SkewFamily Xs
A : Set ι
e : α
i : ι
hi' : e ∈ (fun i => ⋃ (_ : i ∈ A), Xs i) i
j : ι
hj' : e ∈ (fun i => ⋃ (_ : i ∈ Aᶜ), Xs i) j
⊢ e ∈ M.cl ∅