convert (h.subtype A).basis_iUnion <;> simp
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.ModularBase B Xs
A : Set ι
⊢ M.Basis ((⋃ i ∈ A, Xs i) ∩ B) (⋃ i ∈ A, Xs i)
no goals