Theorem: Matroid.Minor.D_coindep (Matroid/Minor/Basic.lean)

State before:
α : Type u_1
M M' N : Matroid α
e f : α
I J R B X Y Z K : Set α
M₀ M₁ M₂ : Matroid α
h : N ≤m M
⊢ M.Coindep h.D
Tactic:
obtain ⟨-,h,-⟩ := h.exists_contract_indep_delete_coindep.choose_spec.choose_spec
State after:
case intro.intro
α : Type u_1
M M' N : Matroid α
e f : α
I J R B X Y Z K : Set α
M₀ M₁ M₂ : Matroid α
h✝ : N ≤m M
h : M.Coindep ⋯.choose
⊢ M.Coindep h✝.D

State before:
case intro.intro
α : Type u_1
M M' N : Matroid α
e f : α
I J R B X Y Z K : Set α
M₀ M₁ M₂ : Matroid α
h✝ : N ≤m M
h : M.Coindep ⋯.choose
⊢ M.Coindep h✝.D
Tactic:
exact h
State after:
no goals