refine ⟨fun h ↦ ?_, fun ⟨Is, hdj, hIs, hb⟩ ↦ hIs.indep.skewFamily_of_disjoint_bases hdj hb⟩
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
⊢ M.SkewFamily Xs ↔ ∃ Is, Pairwise (Disjoint on Is) ∧ M.Basis (⋃ i, Is i) (⋃ i, Xs i) ∧ ∀ (i : ι), M.Basis (Is i) (Xs i)
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
⊢ ∃ Is, Pairwise (Disjoint on Is) ∧ M.Basis (⋃ i, Is i) (⋃ i, Xs i) ∧ ∀ (i : ι), M.Basis (Is i) (Xs i)