induction as
α : Type u_1
β : Type u_2
r : α → β → Prop
as : List α
⊢ List.forAllRel r as [] = True
case nil
α : Type u_1
β : Type u_2
r : α → β → Prop
⊢ List.forAllRel r [] [] = True

case cons
α : Type u_1
β : Type u_2
r : α → β → Prop
head✝ : α
tail✝ : List α
tail_ih✝ : List.forAllRel r tail✝ [] = True
⊢ List.forAllRel r (head✝ :: tail✝) [] = True