Theorem: Matroid.skew_of_subset_coloops (Matroid/Modular.lean)

State before:
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
K : Set α
hK : K ⊆ M✶.cl ∅
hX : X ⊆ M.E
hdj : Disjoint K X
⊢ M.Skew K X
Tactic:
rw [skew_iff_contract_restrict_eq_restrict, contract_eq_delete_of_subset_coloops hK,
  delete_eq_restrict, restrict_restrict_eq]
State after:
case hR
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
K : Set α
hK : K ⊆ M✶.cl ∅
hX : X ⊆ M.E
hdj : Disjoint K X
⊢ X ⊆ M.E \ K

State before:
case hR
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
K : Set α
hK : K ⊆ M✶.cl ∅
hX : X ⊆ M.E
hdj : Disjoint K X
⊢ X ⊆ M.E \ K
Tactic:
rwa [subset_diff, and_iff_left hdj.symm]
State after:
no goals