rw [restrict_cl_eq', diff_eq_empty.mpr hR, union_empty, inter_eq_self_of_subset_left hXR]
α : Type u_1
ι : Type u_2
M✝ : Matroid α
F I J X Y B C R : Set α
e f x y : α
M : Matroid α
hXR : X ⊆ R
hR : autoParam (R ⊆ M.E) _auto✝
⊢ (M ↾ R).cl X = M.cl X ∩ R
no goals