Lemma funextsec_id' {C : univalent_category} (T : C -> C -> C) : toforallpaths (λ _ : C, C → C) T T ( (funextsec (λ _ : C, C → C) T T (λ x : C, funextsec (λ _ : C, C) (T x) (T x) (λ x0 : C, idpath (T x x0))))) = toforallpaths (λ _ : C, C → C) T T (idpath T). Proof. etrans. { apply toforallpaths_funextsec. } apply funextsec ; intro x. apply (cancellation_lemma _ _ _ (toforallpaths (λ _: C,C) (T x) (T x))). - intro q. apply funextsec_toforallpaths. - apply funextsec_id''. Qed.
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import UniMath.CategoryTheory.DisplayedCats.Core. Require Import UniMath.CategoryTheory.DisplayedCats.Functors. Require Import UniMath.CategoryTheory.DisplayedCats.Total. Require Import UniMath.CategoryTheory.DisplayedCats.Constructions. Require Import UniMath.Bicategories.Core.Bicat. Require Import UniMath.Bicategories.Core.Examples.BicatOfUnivCats. Require Import UniMath.Bicategories.Core.Invertible_2cells. Require Import UniMath.Bicategories.DisplayedBicats.DispBicat. Require Import UniMath.Bicategories.DisplayedBicats.DispUnivalence. Require Import UniMath.Bicategories.DisplayedBicats.DispInvertibles. Require Import UniMath.Bicategories.Core.Univalence. Require Import UniMath.Bicategories.MonoidalCategories.UnivalenceMonCat.CurriedMonoidalCategories. Import TensorNotation. Import TensorNotation.