Definition sigma_twosided_disp_cat_id_comp : twosided_disp_cat_id_comp sigma_twosided_disp_cat_ob_mor. Proof. simple refine (_ ,, _). - simple refine (λ x y xy, id_two_disp (pr1 xy) ,, _). apply (@id_disp (total_twosided_disp_category D₁) D₂). - exact (λ x₁ x₂ x₃ y₁ y₂ y₃ xy₁ xy₂ xy₃ f₁ f₂ g₁ g₂ fg₁ fg₂, pr1 fg₁ ;;2 pr1 fg₂ ,, (pr2 fg₁ ;; pr2 fg₂)%mor_disp). Defined.
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.Univalence. Require Import UniMath.CategoryTheory.DisplayedCats.Core. Require Import UniMath.CategoryTheory.DisplayedCats.Isos. Require Import UniMath.CategoryTheory.DisplayedCats.Univalence. Require Import UniMath.CategoryTheory.DisplayedCats.Projection. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Isos. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Univalence. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Discrete. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Total. Section FromSigmaIso. End FromSigmaIso.