case nil => simp; exact h_indsss
α : Type u
inst✝ : Category α
asss : List (List (List α))
h_indsss :
  joinF.associatorLeft asss ≫ joinF.associatorRight asss =
    𝟙 (Prefunctor.obj (Prefunctor.obj mapF.toPrefunctor joinF ⋙ joinF).toPrefunctor asss)
⊢ joinF.associatorLeft ([] :: asss) ≫ joinF.associatorRight ([] :: asss) =
    𝟙 (Prefunctor.obj (Prefunctor.obj mapF.toPrefunctor joinF ⋙ joinF).toPrefunctor ([] :: asss))
no goals