case nil => simp; exact h_indsss
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)
⊢ joinF.associatorRight ([] :: asss) ≫ joinF.associatorLeft ([] :: asss) =
    𝟙 (Prefunctor.obj (joinF ⋙ joinF).toPrefunctor ([] :: asss))
no goals