rw [loopEquiv_iff_union_eq_union, contract_loops_eq, diff_union_self]
α : Type u_1
M✝ N : Matroid α
I J C D X✝ Y✝ Z : Set α
e f : α
M : Matroid α
X Y : Set α
⊢ (M ／ X).LoopEquiv (Y \ (M.cl X \ X)) Y
no goals