Theorem: Matroid.contract_delete_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 M : Matroid α
C D C' D' : Set α
h : Disjoint C' D
⊢ M ／ C ＼ D ／ C' ＼ D' = M ／ (C ∪ C') ＼ (D ∪ D')
Tactic:
rw [contract_delete_contract_delete', sdiff_eq_left.mpr h]
State after:
no goals