α : Type u_1
a : List α
l : List (List α)
⊢ Sections ↑(↑a :: List.map (fun l => ↑l) l) =
    ↑(List.map (fun l => ↑l) (List.bind (List.sections l) fun s => List.map (fun a => a :: s) a))
α : Type u_1
a : List α
l : List (List α)
⊢ Sections ↑(List.map (fun l => ↑l) (a :: l)) = ↑(List.map (fun l => ↑l) (List.sections (a :: l)))
simp
α : Type u_1
a : List α
l : List (List α)
⊢ (bind ↑(List.map (fun l => ↑l) (List.sections l)) fun b => map (fun a => a ::ₘ b) ↑a) =
    ↑(List.map (fun l => ↑l) (List.bind (List.sections l) fun s => List.map (fun a => a :: s) a))
α : Type u_1
a : List α
l : List (List α)
⊢ Sections ↑(↑a :: List.map (fun l => ↑l) l) =
    ↑(List.map (fun l => ↑l) (List.bind (List.sections l) fun s => List.map (fun a => a :: s) a))
rw [← cons_coe, sections_cons, bind_map_comm, coe_sections l]