`{Univalence} (P : AbGroup) `{IsAbProjective P} : forall A, forall E : AbSES P A, tr E = point (Ext P A). Proof. intros A E. apply iff_ab_ext_trivial_split. exact (fst (iff_isabprojective_surjections_split P) _ _ _ _). Defined.
Require Import Basics Types Truncations.Core. Require Import Pointed WildCat. Require Import Truncations.SeparatedTrunc. Require Import AbelianGroup AbHom AbProjective. Require Import AbSES.Pullback AbSES.Pushout AbSES.BaerSum AbSES.Core.