Theorem: Matroid.restriction_emptyOn_iff (Matroid/Minor/Basic.lean)

State before:
α : Type u_1
M M' N : Matroid α
e f : α
I J R B X Y Z K E : Set α
⊢ M ≤r emptyOn α ↔ M = emptyOn α
Tactic:
refine ⟨fun h ↦ minor_emptyOn_iff.1 h.minor, ?_⟩
State after:
α : Type u_1
M M' N : Matroid α
e f : α
I J R B X Y Z K E : Set α
⊢ M = emptyOn α → M ≤r emptyOn α

State before:
α : Type u_1
M M' N : Matroid α
e f : α
I J R B X Y Z K E : Set α
⊢ M = emptyOn α → M ≤r emptyOn α
Tactic:
rintro rfl
State after:
α : Type u_1
M' N : Matroid α
e f : α
I J R B X Y Z K E : Set α
⊢ emptyOn α ≤r emptyOn α

State before:
α : Type u_1
M' N : Matroid α
e f : α
I J R B X Y Z K E : Set α
⊢ emptyOn α ≤r emptyOn α
Tactic:
exact Restriction.refl
State after:
no goals