simp
α : Type u
inst✝ : Category α
asss : List (List (List α))
h_indsss : joinF.associatorRight asss ≫ joinF.associatorLeft asss = 𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor asss)
ass : List (List α)
h_indss :
  joinF.associatorRight (ass :: asss) ≫ joinF.associatorLeft (ass :: asss) =
    𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor (ass :: asss))
a : α
as : List α
h_inds :
  joinF.associatorRight ((as :: ass) :: asss) ≫ joinF.associatorLeft ((as :: ass) :: asss) =
    𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor ((as :: ass) :: asss))
⊢ joinF.associatorRight (((a :: as) :: ass) :: asss) ≫ joinF.associatorLeft (((a :: as) :: ass) :: asss) =
    𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor (((a :: as) :: ass) :: asss))
α : Type u
inst✝ : Category α
asss : List (List (List α))
h_indsss : joinF.associatorRight asss ≫ joinF.associatorLeft asss = 𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor asss)
ass : List (List α)
h_indss :
  joinF.associatorRight (ass :: asss) ≫ joinF.associatorLeft (ass :: asss) =
    𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor (ass :: asss))
a : α
as : List α
h_inds :
  joinF.associatorRight ((as :: ass) :: asss) ≫ joinF.associatorLeft ((as :: ass) :: asss) =
    𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor ((as :: ass) :: asss))
⊢ DVect2.cons (𝟙 a) (joinF.associatorRight ((as :: ass) :: asss) ≫ joinF.associatorLeft ((as :: ass) :: asss)) =
    DVect2.cons (𝟙 a) (𝟙 (as ++ Prefunctor.obj joinF.toPrefunctor (ass ++ Prefunctor.obj joinF.toPrefunctor asss)))