Theorem: Matroid.Flat.cl_exchange (Matroid/Flat.lean)

State before:
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
hF : M.Flat F
he : e ∈ M.cl (insert f F) \ F
⊢ f ∈ M.cl (insert e F) \ F
Tactic:
nth_rw 2 [← hF.cl] at *
State after:
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
hF : M.Flat F
he : e ∈ M.cl (insert f F) \ M.cl F
⊢ f ∈ M.cl (insert e F) \ M.cl F

State before:
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
hF : M.Flat F
he : e ∈ M.cl (insert f F) \ M.cl F
⊢ f ∈ M.cl (insert e F) \ M.cl F
Tactic:
exact Matroid.cl_exchange he
State after:
no goals