rw [← contract_inter_ground_eq, flat_contract_iff]
α : Type u_1
M : Matroid α
I F X Y F' F₀ F₁ F₂ P L H H₁ H₂ H' B C K : Set α
e f : α
⊢ (M ／ C).Flat F ↔ M.Flat (F ∪ C ∩ M.E) ∧ Disjoint F (C ∩ M.E)
no goals