`{Univalence} {A B : AbGroup} (E : AbSES B A) : abses_baer_sum (abses_pullback (-grp_homo_id) E) E = point (AbSES B A) := baer_sum_commutative _ _ @ baer_sum_inverse_l _.
Require Import Basics Types. Require Import WildCat Pointed.Core. Require Import AbGroups.AbelianGroup AbGroups.Biproduct AbGroups.AbHom. Require Import AbSES.Core AbSES.Pullback AbSES.Pushout AbSES.DirectSum. Require Import Homotopy.HSpace.Core.