fact: Definition abses_pullback_projection_morphism {B A : AbGroup} (E : AbSES B A) : AbSESMorphism (pt : AbSES E A) E.
imports: Basics Types HSet Limits.Pullback WildCat Pointed.Core Homotopy.ExactSequence Modalities.ReflectiveSubuniverse AbGroups.AbelianGroup AbGroups.AbPullback AbGroups.Biproduct AbSES.Core AbSES.DirectSum