Theorem: Matroid.emptyOn_cl_eq (Matroid/Closure.lean)

State before:
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
X : Set α
⊢ (emptyOn α).cl X = ∅
Tactic:
rw [← subset_empty_iff, ← emptyOn_ground]
State after:
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
X : Set α
⊢ (emptyOn α).cl X ⊆ (emptyOn α).E

State before:
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
X : Set α
⊢ (emptyOn α).cl X ⊆ (emptyOn α).E
Tactic:
apply cl_subset_ground
State after:
no goals