rw [cons_bind, map]
α β : Type u
γ : Type w
f : α → β
a : α
as : List α
⊢ (List.bind (a :: as) fun a => [f a]) = map f (a :: as)
α β : Type u
γ : Type w
f : α → β
a : α
as : List α
⊢ ([f a] ++ List.bind as fun a => [f a]) = f a :: map f as