case fst_lt_snd =>
  have := hhook.fst_lt_snd
  simp [List.forAllRel_cons_left] at this
  exact this.right
α : Type u_1
r : α → α → Prop
inst✝ : Trans r r r
a : α
as bs : List α
hhook : HookedAscending r (a :: as) bs
⊢ List.forAllRel r as bs
no goals