case cons a as h_ind =>
  dsimp [List.forAll]
  rw [h_ind]
α : Type u_1
β : Type u_2
p : β → Prop
f : α → β
a : α
as : List α
h_ind : forAll p (map f as) = forAll (p ∘ f) as
⊢ forAll p (map f (a :: as)) = forAll (p ∘ f) (a :: as)
no goals