proposition: Lemma transported_comonoid_laws_assoc : comonoid_laws_assoc L (a,, transported_comonoid_data).
proof: Proof. unfold comonoid_laws_assoc. cbn. unfold transported_comonoid_comult_data. rewrite tensor_mor_left. rewrite tensor_mor_right. rewrite ! tensor_comp_id_l. rewrite ! tensor_comp_id_r. rewrite ! assoc. etrans. 2: { do 2 apply maponpaths_2. exact (! diagram_2). } etrans. { do 3 apply maponpaths_2. exact diagram_1. } etrans. 2: { apply maponpaths_2. rewrite assoc'. apply maponpaths. apply tensor_swap'. } etrans. 2: { rewrite assoc. do 2 apply maponpaths_2. rewrite assoc'. apply maponpaths. rewrite <- tensor_mor_left. apply comonoid_to_law_assoc. } rewrite tensor_mor_right. rewrite ! assoc'. do 2 apply maponpaths. rewrite <- tensor_split'. etrans. 2: { apply maponpaths. apply tensor_lassociator. } rewrite ! assoc. apply maponpaths_2. rewrite <- tensor_split. do 2 rewrite <- tensor_comp_mor. apply maponpaths. exact (id_right _ @ ! id_left _). Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.DisplayedCats.Core UniMath.CategoryTheory.Monoidal.Categories UniMath.CategoryTheory.Monoidal.Comonoids.Category UniMath.CategoryTheory.Retracts