Theorem: Matroid.minor_iff_exists_contract_delete (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
x✝ : ∃ C D, N = M ／ C ＼ D
C D : Set α
h : N = M ／ C ＼ D
⊢ N ≤m M
Tactic:
rw [h]
State after:
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
x✝ : ∃ C D, N = M ／ C ＼ D
C D : Set α
h : N = M ／ C ＼ D
⊢ M ／ C ＼ D ≤m M

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
x✝ : ∃ C D, N = M ／ C ＼ D
C D : Set α
h : N = M ／ C ＼ D
⊢ M ／ C ＼ D ≤m M
Tactic:
apply contract_delete_minor
State after:
no goals